Align Slant Thread Main Drive Gear/121T T-REX 450 Series. This is the Align set of three 121T Slant Thread Main Drive Gears for the T-Rex 450 Helicopter. These Main Drive Gears require the Align Motor Pinion Helical Gear 12T (AGNH45157).Features:Black coloredMade of high strength polymer plasticSet of three Built in fan designFor the Align T-Rex 450 HelicoptersThese gears feature a new increased gear pitch that can withstand more power, and at the same time minimize operati