Meet the RNGR ST-2: one of the thinnest, lightest 440C stainless steel knives money can buy. It weighs only 1.4oz and has a blade that measures 2.2″. The blade is removable. The ST-2 can fit in your wallet or hang from your belt.
This handy knife is available for as low as $44 if you order early. More info is available here.