Type SH spring hangers comprise steel springs mounted in a steel housing. The springs are retained between steel top and bottom load plates. Type SH requires the lower hanger rod to pass through the spring with the rod held on top of the spring with a nut and washer.
Type SHA is supplied with a drop rod passing through the spring fixed to the top of the spring with a nut. A tapped adaptor is supplied to fit in a drop rod by others.