A tiny keychain knife with an Exacto style blade, nice for precise cutting but too delicate to be called general purpose. I just got two of them, pretty cool. Dimensions about 50mm long, 14mm wide, 4.5mm thick with the slider bulging up another 1.5mn or so. It's a pretty no nonsense design unlike some fancy and expensive ones I've seen in similar formats. Photo of the back side below:
Added: another good alternative, Derma-Safe folding razor, 7.6g, lacks a lanyard hole. I'm not sure if there's a good place to drill one. Review. The Derma-Safe is too long to fit into an Altoids tin "crossways" while the Ghost EDC will fit that way, if that matters to you.