Review overview



9.5 tech score They are strong, and puncture resistant with a tinsel strength of 3,720 pounds per square inch.

Information about the O.P. Sak Odor Proof Barrier Bag

Description, year of manufacturer and MSRP: O.P. Sak Odor Proof Barrier bags were manufactured by Watchful Eye Designs in 2004. The barrier bags are a superior zip lock bag, well they are a polyethylene bag with a patented zip-lock type closure. According to the literature supplied with the bags, the O.P. Saks have identical seals to the ALOKSAK bags (also manufactured by Watchful Eye Designs.) What distinguishes these bags is the barrier film applied to the O.P. Saks. According to Linda Kennedy of Watchful Eye Designs, the film applied to the O.P. Saks is not as durable as that applied to the ALOKSAK. Three O.P. SAK Barrier Bags (12.5″ X 15.5″) have suggested retail price of $10.59 US and three O.P. SAK Barrier Bags (9″ X 6″) have suggested retail price of $7.49 US.

Weights and Measurements: No weights are listed on the manufacturer’s website. My weights, as weighed on my Arlec digital kitchen scales are 0.95 oz (27 g) for the 12.5″ x 15.5″ bag and 0.25 oz (7 g) for the 9″ x 6″ bag. The manufacturer’s measurements are 9″ x 6″ (229 mm x 152 mm) and 12.5″ x 15.5″, (318 mm x 394 mm) respectively. My measurements are 9″ x 6″ (229 mm x 152 mm) and 12.5″ x 16″ (318 mm x 407 mm) respectively.

My Experience Using the O.P. Sak Odor Proof Barrier Bag in the Field

Testing Location Overview: The hiking environment of the southwest of Western Australia allows for hiking and backpacking from coastal plains to the forest. Elevation ranges from 0 to 585 meters . Within this region, I hike in different situations from forestry roads to sandy tracks to single-purpose walking trails, to rock hopping, to beach walking to completely off- driving through an open and dense country.

Weather Conditions: During the summer period, daytime temperatures average 30 C (86F), whereas from March through to December the daytime average temperatures range from 15C to 26C (59F to 79F). During the autumn, winter, & spring periods the typical weather model is relatively wet with frequent heavy rainstorms evident.

According to The Times Atlas of the World, our weather is described as being “Mediterranean – rainy climates with mild winters, coolest month above 0C (32 F), but below 18C (64 F); warmest month above 10 C (50 F).” The atlas depicts the seaside area north of Los Angeles as having the same climate.

Field experience:

Since posting my Initial Report on March 2004, I have used the O.P. Saks on two-weekend bush walks, numerous day walks and as food storage bags between walks. The two-weekend bush walks have seen me camping at Long Point and Swamp Oak campsites, both on the Bibbulmun Track and both known for rodent visitors. The campsites provided me with an opportunity to leave rubbish in the O.P. Saks which were exposed overnight to see if any residents found the contents of interest. In summary, I have not experienced any attacks on the substance. That said, my experience with the Saks has been variable, and this is discussed in the context of the manufacturer’s claims below. Watchful Eye Designs make four specific claims in respect of the O. P. Saks. They are:

That the bags are liquid & air tight. The bags are certified 100% leak proof to 200′ (61 m) under water or 300′ (67 m) depending on what literature is referred to;

  1. that the bags are durable and safe;
  2. fully recyclable;
  3. soft-sided; quiet and shatterproof.

My experience in respect of these claims is outlined below:

Claim 1: That the bags are liquid and air tight. The bags are certified 100% leak proof to 200′ (61 m) under water or 300′ (67 m) depending on what literature is referred to.

First and foremost as outlined in my Initial Report, for this claim to be valid, the O.P. Saks need to be sealed according to the manufacturer’s instructions, i.e., a small amount of air has to be trapped inside the bag, and the zipper completely sealed ensuring no kinks or bends in the seal.

My initial at home testing in the sink quickly proved the importance of following these instructions! It seems, based on my experience, that leaving that small amount of air trapped inside the Sak is important. Similarly, based on my knowledge on the weekend bushwalk to Long Point campsite it is important to not only seal the Sak correctly but also to be reasonable regarding the amount material placed in the bag.

On that walk, on a Friday night I had filled one large Sak with various food items and had sealed the bag I believe by the instructions. However, upon arriving at the Long Point campsite and unpacking my pack, I found that the Sak had burst open at the seal.

No damage to the Sak was evident. I can only put this down to one of three things: (a) incorrectly sealed by me; (b) overfilled or (c) the Sak did not seal as per the manufacturer’s claims. I suspect the cause of the problem was that I overfilled the Sak as I have since taken care to no more than 3/4 fill the Saks and have not managed a repeated burst.

My second test with the O.P. Saks has been to place some food rubbish in them and then leave them “outside” overnight at both the Long Point and Swamp Oak campsites. Experience has shown that Bibbulmun Track campsites have become known to the local native rodent population as well stocked supermarkets. Both campsite registers also indicated recent rodent activity.

I am pleased to report that on both occasions, upon checking on the following morning I was not able to ascertain any evidence of rodent interest. That said, it should be noted that no human residents of the huts reported any rodent activity either, which doesn’t mean there wasn’t any, but this may have been the case.

My third test of the O.P. Sak’s claim of being air tight has been too full one Sak with freshly purchased nuts and one Sak with an opened packet of water crackers. Both Saks were filled in March and have had their contents consumed over the field test period. In fact, the Sak containing the nuts has been refilled on occasion as it has been used as my trail Scroggin. My experience has been that the Saks have been very effective at keeping both the nuts and crackers fresh, suggesting a good air tight seal as claimed.

In summary, overall I am happy with the performance of the O.P. Sak’s air tight seals to date.

Claim 2: That the bags are durable and safe.

In respect of the “safe” claim, I can’t comment as I am not qualified nor am I am undertaking tests to ascertain whether any leeching or other harmful effects are taking place. That said, I have stored food in the Saks, and I have consumed food stored in the Saks and I have not experienced any known adverse effects at this point.

Durability is another matter. I took the claim of durability as implying that the Saks would be ok to fill with food and store directly in my backpack or day pack as desired. It seems, in light of the further comment by Watchful Eye Designs, that my idea of durability may not be correct. It appears that while the Saks may not need treating with “kid gloves” some “reasonable care” is required. I have now moved to using my Saks inside a nylon stuff sack with the intention of providing some protection from the rough and tumble of life inside my packs.

After using the supplied Saks over the Field test period of two months, I have one large Sak which I find hard to seal and this same large Sak and one small Sak showing great signs of wear including holes. I no longer consider either Sak functional as designed.

While I accept that these are “plastic” bags, the manufacturer has made claims of durability. I may have interpreted those claims unreasonably; however, I would suggest that Watchful Eye Designs more clearly spells out its claims of sustainability and considers providing care and use instructions.

I have also exposed the large Sak which is no longer okay to use to the washing machine as the bag is claimed to be “reusable” and throwing it in the wash seemed a good way to clean it. Maybe that was not a good idea! Again, clear care instructions would be beneficial in my opinion.

For the remainder of the testing, I intend to enclose any Saks used in my packs inside nylon stuff sacks to reduce the risk of damage.

Claim 3: Fully recyclable.

I inadvertently made a misleading statement in the Initial Report on the issue of recyclability. The large O. P. Saks do have a recycling symbol on them which is contrary to my original comments. The small Saks, however, lack the recycling symbol. The recycling code on the fat Saks is Four (4). Unfortunately, my local council’s recycling program will only accept plastics coded One (1) and Two (2), so the damaged or unusable Saks are destined for the rubbish.

Claim 4: Soft-sided; quiet and shatterproof.

Well that the bags are soft-sided, they are as quiet in my view as are other “plastic” bags when crunched and I have not shattered one as yet, so I guess at this point these claims are sustained.

Concluding comments:

Overall I am happy with my experience with the Watchful Eye Designs O. P. Saks. That said I am less than fascinated with their durability but will be taking greater care for the remainder of the test. I do like these Saks, and I am impressed with the evidence I have to date of their abilities against rodents. Something I find particularly useful!


Tags : Odor Proof Barrier Bagtips
Andrew Priest

The author Andrew Priest

I am a 44 years old male, 180 cm (5' 11") in height and I weigh 100 kg (220 lbs). I have been hiking in Western Australia for approximately five years. For the past four years I have been regularly walking and now leading walks with the Perth Bushwalkers Club. These bushwalks range from all on-track to all off-track pack-carries. I consider myself as moving towards being a lightweight tent-carrying bushwalker with my pack base weight in the 8 to 12 kg (18 to 26 lb) range. In 2003 I completed my End to End of the Bibbulmun Track. I have also end to ended the Cape to Cape Track and the Coastal Plains Walk Track.

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