The R3 (RP-3401) and R3HV (RP-4401-HV) are both undoubtedly the best low profile servos you can find on the market. It has Xpert's quick release connectors with multiple length options. The R3HV has the center and top aluminum case with extremely good thermal dissipation performance. The R3 has the center piece with aluminum and lower/ upper case with engineering plastic. Both R3 and R3HV utilize the highest strength stainless steel gears for the best durability.
The R3 and R3HV are both compatible with the ultra fast response Sanwa SSR mode. Speed, Torque, Accuracy, Durability, Flexibility and Looking are the combination we have put in mind to make this all new R3 series!!