The extendable boom arm fits on the LS-3FH Light stand and works with the removable end mount or the magnetic mount

This replacement pivot block fits into the 1-1/6″ round down tube and accepts a 7/8″ diameter boom arm

This replacement boom arm fits the 7/8″ Slide assembly for the LS-1FH, LS-3HC & LS-3FH light stands.