Specs are directly from Overdose website.
"Precision machining full machining, it is highly rigid aluminum gear case set. Possible backlash adjustment accurate high-precision finish. In addition, the high stiffness case to minimize the burden keep me, to the gear position without missing each gear even when using high-power motor. By punching meat that has been subjected to the extreme, and it weighs about 39g up 15g of the normal ratio. Have minimal impact on driving performance. Of course, so durability has improved by leaps and bounds, freed from troubles caused by frequent occurrence of cracks in the normal. Set of gear case x1, individual gear cover x1, x2 mounting screw gear cover of the book "