Flange Motors retracted "cartridge" type, designed to be directly installed on compact planetary gear-wheel Trailering. Five sizes of engine displacement fixed flange SAE Setup. Two sizes of engine cylinder capacity settings fixed flange retracted "cartridge". Two sizes of engine displacement variable in configuration of flange retracted "cartridge SAE". Engines of variable displacement with displacement 3:1 ratio. Variable motors are available with engine displacement of two control positions electro-hydraulic or hydraulic. Small installation dimensions. Pressures up to 480 bar (6962 psi).