NotaPen

Little Titanium stash cans, made to look like a pen.
All the same dimensions and materials as my TiBolts, it even uses the same cap and clip! (The tip will work too, but then it won't be watertight. It is water resistant now.)
These have a roughly 8mm inside diameter, and are about 66mm long inside.
94-125mm long overall, depending on what tips and caps you put on it.
These are long enough to hold toothpicks this time too!!
Stick the Carbide Fake tip on there, and you have a glassbreaker!
Stick a BallBreaker on the other end, and you can break glass coming and going...