Tandem sheave running out block fit for stringing one conductor. Aluminium sheave mounted on sealed ball bearings. Groove lined with nylon sectors. Openable galvanised steel frame with non-fleeting device. Standard swivelling fork attachment. Designed to distribute high working loads over two pulleys. The tandem sheaves are mounted on a special steel frame consisting of a yoke and two arms. The sheaves can also be used as standard single pulleys.