Purchase is for 3 components.  The Pole mount plate has a 2.50" square component mount adapter with numerous threaded holes for clamping.  The MM2 mirror mount has micrometer screws for two axis adjustment.  This has been machined for flatness and has 3-threaded mounting holes.  The U100-A adjustable mount is suitable for any 1" diameter component such as Dichroic filters, mirrors or beam splitters.  All three components are in very good condition.