Opticron Rubber Objective Lens Covers 56mm OG M Pair fits models with Outer Diameter 64~65mmOpticron Objective Lens Covers are a neat solution for protecting binocular objective lenses from rain, dust and dirt while in transit or storage. Covers remain attached to the binocular barrel and hang down when in use. Model fits objective lens barrels with an outer diameter 64-65mm. Remember to measure the OUTSIDE DIAMETER (including armoring) of the barrels of your binoculars to get accurate sizing. Fits Opticron Models: T3 Trailfinder WP 8x56Opticron 40mm BGA Binocular Rainguard,31076,BlackOpticron Binocular Rain guards protect binocular eyepieces from rain, dust, dirt and accidental damage.