Hobbypower CNC Alloy 22mm Tube Boom Mount Motor Clamp for DIY Quadcopter Multirotor(pack of 4 Pcs) For 22mm diameter tube Dimension: approx. 34 x 28 x 5 mm 3-Axis Aircraft:need 12 pcs Quadcopter :need 16 pcs Hexacopter :need 24 pcs