RioRand ES08MA 9g Mini Metal Gear Servo Upgrade mg90s for trex align 450 rc helicopter E (4 Pcs) -Powered by RioRand Advanced Technology -Dimensions:23*11.5*24mm -Operating voltage: 4.8V-6.0V -Operating speed: 0.12/0.10sec/60degree -4pcs X EMAX ES08MA Mini Servo