Available in different sizes:
30010 - 1" with 2 " backplate and 3/4" projection.
30020 - 1-1/4" with 2-1/4" backplate and 3/4" projection.
30030 - 1-1/2" with 2-1/2" backplate and 3/4" projection.
30040 - 2" with 3" backplate and 3/4" projection.