Icemaster makes pebble heads in both 64  hole and 54 hole formats.  Size are read with the number of holes preceding the dash and the diameter of the holes following the dash.   Heads in sizes 64 - 67 and 64-68 are mainly used for the pebble/scrape sequence for ice maintenance ;  and 64-70 and 64-72 are commonly used on arena ice.  All other size combinations are suitable for competition ice making.