This is a 15" weatherane mount rod that can be used with the 2 and 4 sided ez vane roof mounts. Note that the EZ Vane weathervanes include a mounting rod that will fit the 2, 4, post and deck mounts. If you are mounting your vane on top of a cupola, you will need the cupola mounting rod, not this one. This 15" mounting rod product is typically needed for only replacement of a missing or damaged vane mount rod.