For the ultimate in bag protection, Vacmaster use and recommend bone guards to avoid puncturing holes in your vacuum bags. By placing a sheet of Bone Guard over the bone or sharp edge you are vacuum sealing, you will prevent punctures and tears. Ultra heavy duty 152 micron thick material will protect your bags from the sharpest bones. Each sheet is 114x127mm in size and clear for full product visibility. VACMASTER Bone Guard works with all suction and chamber bags and machines. 150 sheets per box.