This is the Futaba BLS251 Brushless Digital Heli Rudder Servo. Designed specifically for helicopter rudder operation. ***Compatible with the Futaba GY520, GY601, GY611 and GY701 gyros.*** This servo can produce high-current draw from your batteries. If using NiMH or LiPo batteries, make sure they are capable of delivering sufficient amps. FEATURES: Equipped with a Brushless motor that lasts longer and operates at a lower temperature than Brushed motors Samarium Cobalt magnets and dual ball bearings 30% faster response times, smoother operation. Same power consumption and centering as Digital servos equipped with Brushed motors Metal gear Compatible with Super Narrow Pulse of (760µs) drive. One-year warranty INCLUDES: Futaba BLS251 Brushless Digital Heli Rudder Servo with universal connector, 0.83" (21mm) diameter round horn pre-mounted 1.8" (45mm) diameter round horn 1.2" (32mm) diameter 6-point horn 1.5" (38.5mm) 4-point horn Servo mounting hardware REQUIRES: Installing in helicopter and plugging into gyro SPECS: Torque @ 4.8V: 53 oz-in (3.8 kg-cm) Speed @ 4.8V: 0.06 sec Dimensions: 1.6 x 0.8 x 1.5" (40 x 20 x 36.8mm) Weight: 2.1oz (59.5g) COMMENTS: This servo will NOT work with the GY240 or the GY401 gyros. jxs 6/25/07 updated 11/09/07kh ir/jxs updated jpg 2/14/08 updated rda 4/2/08 updated jpg 8/13/09