JR/DFA S8411 HV XBus Servo
Specifications: 
@6.6V 15.4kg-cm    Speed: 0.17 sec/60゜
@7.4V 17.3kg-cm    Speed: 0.15 sec/60゜
@8.4V 19.6kg-cm    Speed: 0.13 sec/60゜
Dimensions:  37.5mm x 19.0mm x 34.5 mm