This universal style freewheel spanner from ACS is designed to suit most common freewheels from 13 tooth right up to 22 tooth. It has two heads with a different size 4-lug freewheel remover on each.
The smaller head is for 13 to 15 tooth freewheels with the smaller metric M30x1 mounting that is commonly found on flip-flop hubs. This head has four lugs that are 4mm x 3mm in size. The outside diameter at the outer edge of the lugs is 31mm and the inside diameter is 21mm.
The larger head is for standard freewheels 16 tooth and upwards that fit on the more common 1.375" x 24 hub threading. This head has four lugs that are 8mm x 6mm in size. The outside diameter at the outer edge of the lugs is 40mm and the inside diameter is 27mm.
Both heads are compatible with 3/8" or 14mm axles.