Park Tool CNW-2 Chainring Nut Wrench. The CNW-2 makes chainring bolt and nut installation and removal easy. It securely holds the unique slotted chainring nuts in place to prevent slipping while tightening or loosening the bolt. Double-ended to fit most slotted-type nuts.

The outer width of both ends of the CNW-2 are nominally 12 mm wide

One end has a two outer tips nominally 2.7 mm wide each and the other end has tips of 3.8 mm each

The blade thickness is nominally 1.35 mm