Heavy cast iron with unique locking feature to keep weights in place. Four sizes, available in pairs. Two-piece clamp type.
1/2 # size - openings 3/4" and 1''
3/4 # size - openings 13/16 and 1 1/18"
1 # size - openings 7/8" and 1 1/4"
1 1/2 # size - openings 1" and 1 3/8"