Loft Block Idlers can add to under hung loft blocks to carry the weight of the cables and prevent rubbing against adjacent block side plates. They are not intended to carry line loads or to act as deflector or mule blocks. The idler sheaves have 1/4 inch cable grooves with a 3/8-inch shaft in a 12-gauge steel housing with two 1/4 inch bolts and pipe spacers to mount the housing and captivate the cables in the grooves. The idler assemblies consist of one or two 3-1/2 inch diameter, 3 line nylon sheaves mounted on the side of the loft block in a steel housing.