Fast, flip-open design; custom fit for most scopes Water-tight, custom-fit friction mounts anchors them to your scope; air-tight semi-O-ring keeps out dust and moisture Truly ambidextrous; silent spring hinges won't spook game Instant action lids pop open at the touch of a thumb Performs from -40 to 120 Degrees F.; weighs less than an ounce Flip-Open Scope Cover - 30 Objective1.960" diameterQuiet opening lids flip open at the touch of your thumb - Water-tight friction mount anchor covers to your scope - For right & left-handed shooters - Less than 1 oz.