These Vortex Push-On Objective Caps are originally supplied with the Fury, Razor, and Viper binoculars which have 42mm objective lenses, and are offered here as a replacement for a lost or damaged cap.
They'll also fit many other binoculars as an optional upgrade. It is difficult to say which tethered caps will fit which binocular since the fit is dependent on the objective lens barrel's edge design. Consider the stated 50mm outer barrel diameter estimate, common to many 40-42mm objective binoculars, as a guideline.
