list your pony bottle size options / reasons

[DetectorGuy]

There are pros and cons to everything and it depends on how you intend to use the pony bottle. I try not to buy much of anything that has a "dual role" because what ever that equipment is, would not be able to do both functions perfectly and will have some sacrificing qualities. I use a 19 CF pony attached to my Alum 80. I don't do planned deco dives and use it only as a redundant air source in the event I run out of gas on my primary source. If I was tangled up and out of gas I would literally spend the rest of my life wishing I had a bit bigger "bail-out bottle". Proper air management, and practicing self rescue skills often, would minimize these risks from happening at the same time. The 19 CF works good for me as it is less drag than a 30 or 40 CF stage bottle dangling from my torso. The 19 CF will get me up from 100' safely on its own. With the short hose to the second stage it does not lose much air while bleeding it off after a dive. I only top it off after every 20 dives or so. My opinions may not be correct but thats the way I look at it.

Some of the draw backs to using a 19 CF attached to your main tank:
1. You can not hand it off to your buddy (which can be a plus as You can not drop it while doing this)
2. It has 1/3 as much air as a 30 and 1/2 as much as a 40. (depending on your SAC rate, depth or distance to the ice hole, you might need this extra air in a true "out of air" situation.)
3. The short hose on mine makes sharing it with your buddy tougher (comfort does not matter to me during emergencies)
4. The small button pressure gauge on mine attached directly to the first stage is impossible to see during the dive. (to me this is irrelevent as I check the pressure prior to the dive and when I switch to it, I already have more important things to take care of.)
5. The small stature of the 19 CF doesnt look cool like a 30 or 40 CF 8)