... ,420,428,428H,520,530,630,25,25H3)short pitch conveyor roller chain attachments:A-1,A-2.K-1,K ... -2,SK-A,SK-2 etc4)double pitch transmissions v& conveyor chains :2040,2042,2050,2052,2060,2062,2060H,2062H,2080 ... ,6)simplex,double,triplex chainsThe chain technic is as bellow1)shot peening2)bluing3)phosphating4)nickel-plated5)zincing6)heat treatment7)greasing8)quenching9 ...