This Tenebraex clear ocular flip cover is designed for Vortex Viper riflescopes. It can conveniently flip out of the way when you are ready to shoot and will protect your lens from damage. Fits the Following Vortex Viper Scope: Viper 6-24x50Fits the Following Vortex Viper HS Scopes: Viper HS 2.5-10x44Viper HS 4-16x44Viper HS 4-16x50Viper HS LR 4-16x50Viper HS LR 6-24x50Fits the Following Vortex Viper HST Scopes: Viper HST 4-16x44Viper HST 6-24x50Fits the Following Vortex Viper PST Scopes: Viper PST 1-4x24Viper PST 2.5-10x32Viper PST 2.5-10x44Viper PST 4-16x44Viper PST 4-16x50Viper PST 6-24x50 Tenebraex Ocular Clear Cover w/Adapter ring for Vortex Vipers UAC018-CCR