The “extreme speed” HSG-5084MG Digital Micro Tail Rotor servo is based of the HSG-5083 but utilizes a standard frame rate digital amplifier. Designed to work with most gyros the HSG-084MG is designed to to obtain optimum performance in the T-Rex 400-450, Helimax 400-450 or similar class of electric helis.
Specifications

Motor Type:3 Pole
Bearing Type:Metal Gear
Speed:0.07 / 0.05 sec @ 60 deg.
EnglishMetric
Torque:21 / 26 oz.in (4.8v/6v)1.5 / 1.9 kg.cm
Size:13.00″ x 1.14″ x 1.18″29.00 x 30.00 x 0.51mm
Weight:0.78oz21.70g