This is the HS-805BB Mega 1/4 Scale Ball Bearing Servo from Hitec. Known as the “monster” servo the HS-805BB uses a heavy duty nylon gear train and a strong 10mm, 15 tooth output shaft to generate 343in./oz. of torque that will easily move just about any large plane, car, truck or boat!

Specifications:
Transit time: 0.19 sec/ 60 deg. @ 4.8V (0.14 sec/deg @ 6V)
Torque: 275 oz/in @ 4.8V (343 oz/in @ 6V)
Weight: 152.0g (5.36 oz)
Length: 66mm (2.59")
Width: 30mm (1.18")
Height: 60mm (2.26")