Water jacket for the TP Power 3630, 3640 and 3650 V1 & V2 version motors. 45mm (1.77") long, the jacket is long enough to cool the motor well. Yet weighs just 2 ounces. Installation is a snap! Apply some oil/grease to your motor housing and the o-rings on the jacket, than slide on the jacket. Specs: Approx. 1.77" (45mm) long x 1.58" (40mm) outside diameter. Note: This jacket fits both the TP V1 & V2 Series Motors