Getaprop r & d flexible coupling http://www.getaprop.com/ Sat, 4 Feb 2012 14:32:10 -0600 en 4" Borg Warner... The R & D Flexible Coupling fits between the transmission output flange and shaft coupling. It is designed to protect a boat's drivetrain. The unit will reduce vibration, compensate for some misalignment, isolate the shaft and absorb shock loads. Capacity: HP/RPM=5 (HP x GearRatio x 100/Max Rated RPM) Flange Diameter:4" # Holes:4 Hole Diameter:0.39" Bolt Circle:3.25" Pilot Diameter:2.50" http://www.getaprop.com/content-product_info/product_id-2019/r_d_flex_coupling_910_001.html http://www.getaprop.com/images/products/flexshaftcoupling[1].jpg http://www.getaprop.com/content-product_info/product_id-2019/r_d_flex_coupling_910_001.html