**Please note this is a black set of gears, not white as in the photo.
Use for all T-REX 450 models Must be used with Motor Pinion Helical Gear 12T H45157
New style high strength 121 tooth Mod 0.6 helical main hear for 450 size helis.
The increased gear pitch can withstand higher power, at the same time minimize operational noise.
A great upgrade to withstand the modern high power system.