want the AirTites to be really air-tight to keep gasses from moving into the coin's environment. The two halves of the holder have sides silghtly tapered to make a tight fit. The size of oxygen and nitrogen atoms is on the order of 3 x 10 to the -10th meters, so the gap has to be smaller than that.

A swiss army knife on your keychain means you always have a way to get to your chip in the holder (unless TSA took away your knife at the airport on the way to the chip show ).