ZooziiElipse...there are three sizes in this tool...Mini, Small and Medium. The holes go side to side, creating some great texture in finished jelwery pieces! The measurements are as follows: Thickness for all are 7mm Mini: 16.5mm long by 13mm wide Small: 19mm long by 15 wide Medium: 23 long by 18 wide This tool will accept up to a 3/32nd mandrel. Hint: This tool works well with a "chunky donut bead" as the "pre-press" shape. The donut should be about 1mm thinner on each side then the press is wide.