This Pinlock 120 MaxVision only fits the following visors: KDF16-1 for EXO-R1 Air, EXO-1400 Air, EXO-520 Air and EXO-391.
A Pinlock is a lens that is attached to the inside of the visor to prevent fogging. The Pinlock lens is made of a special moisture-absorbing plastic. The silicone seal on the Pinlock lens creates an insulating layer of air between the Pinlock lens and the visor, just like double glazing.