UL, Completely Sealed Drybag?

1.43 oz./yd. (i.e., heavy!) cuben; the rectangular size is 11" X 20" and it has a super-cool velcro strip along the open side. weighs abut 1 1/2 ozs. I stick my iPad in it with a few other things and it's always been watertight… but I'm chicken and double-bag the iPad witha gallon-sized Zip-loc.

Have fun!

I'd also go with the Zpacks bag. Long as you have enough room to roll the "open" side a couple of times, it'll be GTG.

NM

A simple Hefty trashcompator bag is still the most waterproof thing I've ever come across. If you twist the ends, you can put a simple knot in it.

Velcro roll tops will not keep your things dry during submersion. They work fine for bear bagging and rain, but water *will* find it's way through relatively quickly when submerged.

I have a few few heavier Seattle Sports clear plastic roll top dry bags with rubber seals along the fold that have remained waterproof through extended swims.

When I need to keep electronics and other things 100% dry on canoe trips, I usually double up with quality ziplock-style bags (sometimes Loksaks) inside another roll top dry bag (such as my S2S Nanosil). Often I will wrap the electronics up inside clothes or my sleeping bag so if the outer bag does leak, the clothes/bag will hopefully absorb most of the water before it has a chance to reach the ziplock/electronics.

If you can still find them, the Stoic dry bags with the purge valve is watertight. I had me and my wife's cell phone, keys, wallet, etc in one and strapped to a hydration backpack.

Took it out to go Standup Paddleboarding around the local lake when some dude fishing decided to cast right at/infront of me and I fell trying to avoid his line. I was splashing around and trying to get back on and falling off and swimming around for a couple minutes with the drybag fully submerged and everything was still dry.

Its got a clear TPU top section for a several inches, so when you roll it, that TPU section sticks to itself really well and keeps out the water. The purge valve is the kind you find on thermarest/BA, etc sleeping pads so its water/air tight.

The bottom corners also have strap loops precut out so you can easily lash it down.

These ones… but not in stock..

http://www.backcountry.com/stoic-wpf-compression-sack-3pk

Double (or Triple) up on the heavy duty zip locks has been the most cost effective solution for me.

Not cheap or UL, but I have 2 of these for kayaking and they have proven to be both 100% (submersible) waterproof and bulletproof.

http://www.cascadedesigns.com/sealline/packs-and-duffles/zip-duffle/product

I have two bags a smaller one made of clear vynal plast and the rubber coated fabric one. Yes they are heazvy but I got them for a couple of river rafting trips years ago (one down the grand canyon). Both worked very well and never let water in even when the rafts were full of water after the rapids. If you use the bag in a backpack try and keep the role closure on the bottom. That way the air trapped in willhelp prevent water from getting in.

I have looked at but never purchased fabric dry bags. Just looking at them I was not convinced they would keep my camera dry so I never purchased one.

The Granite Gear ones are quite good. The UL one you need to be careful about abusing the event membrane with excessive pressure if you are compressing stuff too quickly. The heavyweight ones are bomber.

The thing about a roll top is that if you are intending to submerge the thing then you need to roll it correctly. If you do it will stay dry – almost no matter what. If you aren't, and the stuff inside is getting wet then it may be user error. 4-5 TIGHT rolls together with a very tight pack to hold the seal in place. If you are trying to do loose packing, such as throwing your camera in there, then a roll top is not the right choice if immersion is a possibility.

Sealline makes one that I would trust on your bike ants padded too:

http://www.cascadedesigns.com/sealline/urban/computer-sleeve/product

From there, you get into the heavier tarpaulin bags used by sea kayakers. A Pelican case is the ultimate, but bulky and heavy.

I wonder if you can find one of the locking silicone seal food containers that would fit? Add a little bubble wrap for bumps. Lock N Lock and Systema are good brands. I like them for cameras. I wouldn't go there first for a Grand Canyon rafting trip, but I'm confident in them for anything a hiker or traveler would get into.

If I expect a dry bag to be seriously challenged, I rub lip balm on the sealing surfaces before closing it up. Then I'm very anal about not getting any wrinkles in the bag as I roll it down. One trick some folks use is to put some compression on the closed bag from the outside in the hope that any leakage will be from the inside out.

Hmm, close but no cigar on some of these. I don't trust a ziplok bag for repeated use and I'm not looking for padding. Plus, conventional laptop cases are all too big for my tiny netbook.

Also, I am not simply looking for rain-proofing; I'm looking for full submersion protection.

Looking at options for a Seal-Line or an Ortlieb drybag, I was just wondering if anyone happened to know which was the lightest around!