... 3,8 year sprocket and gear factory history 4,standard or non standard Products Feature 1, all made by advanced CNC ... frequency quenching. 4, we also provide nonstandard( according to the customer drawings) and standard(ANDI and the metric system) sprockets ... resistance, low noise, smooth and steady, high strengthModel numberStandard or nonstandard (single duplex and triple)20A10-100, 40A10-100, 60A10 ...