Electric actuator TOPP, Model C20 with double link articulated chain, contained in a suitable casing, complete with support and fitting accessories for top and bottom hung windows. Operation at 230v~ 50Hz or, as an alternative, at 24 V d.c. Maximum applicable load 300N. Rapid coupling for the adjustment to the frame. Stroke adjustment by and external selector, at 24 and 36 cm. CE marked device complying with the following directives: EEC 89/336, EEC 73.23 and following amendments.