Put this on in place of regular tip - has metal center piece that flips down for use outside, and flips up flat when indoors - 16-22 mm. Recommended use outdoors only, and change to regular tip indoors for longer use there. Self-adjustable to smaller sizes down to 3/4". Limited to one BLACK and one BROWN one in stock as of 02.29.08. WILL FIT BUBBASTIKS and WOOD HERCULES CANES! Only 'Ice tip' item that will .... let me know if you need more than two!