This is a 10-pack of the Fixed Mirror Mount. The cost-saving A-LINE™ M-LH-1DB Fixed Double-Bore Mount 10 pack is a convenient and economical solution for mounting Ø1.0 inch (25.4 mm) mirrors, beamsplitters or UPA series 1-in adaptors. The mount consists of a double-bored aperture and set screw to hold the optic firmly, but gently. The holder incorporates an M4 threaded mounting hole for post mounting on Metric SP and MSP Series posts. The front of the holder also has a special 6 mm alignment hole, which can be used with GR Series Guide Rods for fast alignment of several A-LINE™ lens mounts.