Fotogenetic - Gear

I always find it fascinating, to see what other photographers consider their essential equipment - what lenses, what filters, what tripod (with which head), which body(bodies), which flash(es), that sort of thing. What I also find interesting (which isn't, unfortunately, covered in the linked article) is the other stuff that you carry with you - still for photographic purposes, but not photographic equipment as such. For me, on top of the camera gear, I have a few elastic bands, two pens, some model/property release forms, some plain white card (handy for notes, stiff enough to write on without needing something to lean on, and can be used as a flash reflector when combined with the elastic bands) some tissues (for me, not for my lenses of course), a blow-brush, a small pocket knife and (once I get them printed) a few business cards.

So, how about you? Do you have an interesting range of gear? Would you like to share your list with the world? Or do you have a suggestion as to what else I should be carrying with me, that you personally find invaluable?