PAdiver93:
To remove o-rings that get chewed up and need replacing.
I use a small tuff-tote for my save-a-dive kit that goes on the boat with me. Everything else stays in the save-a-dive vehicle.
In the tote stuff is basically divided up by category:
* First Aid - stuff that gets used on other divers unless I screw the pooch;
* Meds - my standards: Triptone/Bonine, Sudafed, Tylenol, Zantac, etc.;
* Sunblock and Chapstick, and a hat to put on during SIs;
* Tools and spare parts - to fix stuff that breaks, extra LP hoses, etc.;
* Spare mask, spare SMB, spare reel, etc. in case dive #1 goes wonky;
* Admin stuff - cert cards & log in a small otter box, cell phone, PDA with tide tables and D-Plan on it, etc.;
* Gas analyzer, tape, and a Sharpie - to check mixes, topoffs, etc;
* Copies of the dive plan and the deco schedule;
The items in the kit are generally there because I've needed them at one time or another (or a buddy has). I also carry a spare DIN reg first stage, (but admit that I don't carry a tank valve! Perhaps on my next live-aboard!) Its a good thing to know what your buddy has, and for your buddy to know what you have, in a save-a-dive kit. Individual needs and preference are different, but when you suddenly need something real bad, knowing where to go to grab it can make a big difference.