JR S588M HV XBus Servo Metal Gear
Specifications: 
@6.6V 6.9kg-cm    Speed: 0.21 sec/60゜
@7.4V 7.7kg-cm    Speed: 0.19 sec/60゜
@8.4V 8.7kg-cm    Speed: 0.17 sec/60゜
Weight: 45 grams
Dimensions:  37.5mm x 19.0mm x 38.5 mm