The black aluminum water-cooling jacket is designed to bring water into direct contact with the motor and allow it to flow around it, maximizing cooling. Includes large o-rings to allow lots of water into the jacket to cool the motor. Fits: 40mm motors, for example, SSS, Leopard, Neu, & TP Power Specs Length: 50mm long (1.97") Diameter: 48mm (1.89") **Motor not included.**
