Leupold Alumina Flip Back Lens Cover 40Mm 59045 n/a Imported Flip-back lens cover designed for Leupold 40mm riflescopes Powerful neodymium magnet holds cover securely over the lens Triple O-ring seals provide max protection; flips open quickly and easily Clockable design lets you rotate cover to open in any direction Machined-aluminum precision construction; available in several sizes