Sonic Mk 2 Hydraulic - The Lower unit is identical to a Standard MK2. The upper unit is manufactured to accept flange mounted hydraulic motors with keydrive, ie. F11-19, F11-28 and F11-39. Specials manufactured also to fit electric motors. These units can be used for main propulsion or bow thruster application maximum input torque 11kg/mtr: Sonic Hydraulic bow thruster (illustrated) available.