The 9530 Series is a surface mounted, single door (pull side) application. The 9540 Series is a surface mounted, single door (push side) application. The 9550 Series is a surface mounted, simultaneous double door application. The 9560 Series is a surface mounted, independent double door application. The 2810 Series is a concealed mount, single door application. The 2850 Series is a concealed mount, simultaneous double door application. The 2860 Series is a concealed mount, independent double door application. Visit the 9500/2800 Series catalog pages for mounting details, arm options and accessories.