The M-163-CM clamp will hold a 4.505" diameter bottle. Mounting holes in the clamp are 1/4"-20 (uses bolt # 48CBH) on 3.610" centers. Used in fresh air bottle applications such as RAFFO. Machined out of 1/2" magnesium. See our tab assortment to find an appropriate mounting tab.Substitute for M-163-BM, open to 4.58" ID if needed.