ROHN WM18D Double Wall Mount with 18" Stand Off - Masts 7/8" to 2-3/4" OD HEAVY DUTY DOUBLE 'Y' STYLE BRACKETS. 2 BRACKETS INCLUDED AS SHOWN. GALVANIZED STEEL WALL MOUNT PROVIDES 18" CLEARANCE TO THE WALL. MASTS ARE HELD IN PLACE WITH 2 UNIQUE 'ANTI-TWIST' LOCKING SCREWS CLAMP ACCEPTS 7/8" TO 2-3/4" OD MAST TUBES. CAN BE USED ON MASONRY, WOOD, METAL, OR OTHER TYPES OF WALLS USING UP TO 1/4" LAG SCREWS OR BOLTS (NOT INCLUDED)