The 15 Series Operators have a high-pressure die-cast zinc housing that is electrostatically coated. The E-Gard coated gear arms and drive worm are made of hardened steel. The #15 Ellipse Dyad Operators are designed for windows from 16" to 24" wide up to 52" high with a maximum sash weight of 52 lbs. when used with the proper 14 Series Casement Hinges. LEFT HAND SHOWN Truth Split Arm Operator 30905 Common number found on this operator is 30905, which is found on the linkage arm, along with 45035 on the body, 40351 and 40352 on the arms. Also known as a TH-24174, TH-24175, TH-24176, and TH-24177. Replaces the TH-24018, TH-24019, TH-24020 and TH-24021. Order stud bracket and handle separately if needed (see related products below). Any handle style will fit.