We’ve seen loads of keychain gadgets before; photo album, flashlight, remote control etc., but never before a Digital Scale Keychain ($13).
Easy-to-use clip makes it simple to weigh small objects like letters, jewelry and coins. Backlit LCD displays weight in grams (g), ounces (oz) penny weights (dwt), or grains (gn). Capacity: 8oz x 0.005oz; 225 x 0.1g.