Sub 2inch OD = hydro exempt. Thankyou military. It doesnt mean you wont get your fill rejected once your tank is over 5 years old, so keep your exemption rule list close at hand if you are counting on your 5+ year old unhydro'd tank to get filled.
13ci and 22ci tanks are really great. It is so nice to use skinnier tanks. Big fat HPA tanks really make guns less comfortable to actually hold.
"I'll see it when I believe it"
PSA: Please don't use photobucket to post images. When you go through one of the older picture threads and find a lot of dead photo links, it is because of photobucket. They limit the amount of bandwidth your free subscription pictures can use, and then make the photo unviewable. Please use imgur.com or another free image host that does not ruin picture threads.