Nikwax Solar & Waterproof Tent & Gear Protector
I have already sprayed down my new tent with this UV/Water proofer with the Nikwax 10 oz bottle. It says the 10 oz bottle will be enough for a 2 person tent; however, I was able to spray down my 67 liter backpack and 25 liter daypacks too. This stuff goes a long way once you wipe the gear/tent down after you've sprayed it. I almost went through a whole paper towel roll wiping my tent down so don't go crazy and empty the bottle on your tent trying to spray and saturate every single little spot. You'll get plenty of coverage when you wipe it down. I have not used my tent and gear in the outdoors yet since spraying it down, but I purchased this product because of all the other high quality reviews it received on here. Will be spending a week in the backcountry of Grand Canyon this July and will be putting it to the test!

Great stuff
There's a reason this stuff gets good reviews - it's easy and it works. The 1L (or 33 oz, whatever) size adequately covered my large tent (like 9'x9'), the fly for that tent, and my 15'x15' 5-sided shade-tent/canopy, with a little left over. Might be enough left to cover my backpacking tent too, but I haven't tried yet. One downside, this size doesn't come with a spray nozzle (not sure why), but just get separate spray bottle - you probably have one laying around somewhere anyways. No more leaks!

Waterproofing two tents
I purchased the Nikwax Tent and Gear Waterproofing after researching tent waterproofing online. The Nikwax was very easy to use, I like the fact that it's a water-based product. I was able to set my tents up inside the house and treat them inside since I have plenty of extra space. I was able to treat a new Marmot 3-person tent and a well-used REI 2-person tent with a 32 oz. bottle. I used several coats on the REI tent since it's 12 years old. I took the Marmot out last weekend, it didn't rain, but I am sure the waterproofing will get tested in the near future.

Works great
Purchased the 500ml bottle to weatherproof a one man tent fly. I applied two coats and used 3/4 of the bottle. Easy to apply and works great. Eliminated the fly from wetting through to the tent fabric.

great stuff
bought the 500ml bottle for weatherproofing a canopy cover on the patio 10 ft x 10 ft. I wish I had bought a larger bottle. Still it worked great . Easy to use and effective at keeping us and our chairs dry. Thanks, Fast shipping too!