The DERTEC cast iron TS/TSA series Helical wormgear drives are available in 4 different sizes. TS(A)38, TS(A)48, TS(A)58, TS(A)68. The use of a Helical gearset increases the final ratio and offers a relatively high effciency. The basic sizes such as footprint, shaft diameter and height are according to the most commonly used sizes. Assembling from stock is possible for many different combinations..