Alumina flip-back lens covers feature powerful neodymium magnets to hold them securely closed and triple O-ring seals for maximum protection from the elements. Their machined-aluminum precision construction, quick and easy operation, and a low-profile position when open make our flip-back lens covers stand above the rest. The round objective models are clockable, so you can rotate them to open any direction. Available in a variety of sizes for both eyepieces and objectives