O'Neill - MUTANT 6/5/4 IST BOOTONeill Mutant Boot 6mm neoprene in the thickness area Internal Split Toe Glued and Blindstitched Color: Black Graphite Size: 8 9 10 11 12 (US Sizes) The O'Neill Mutant 6 5 4mm boots offers a split toe design along with enough neoprene to keep your feet warm throughout even the coldest winter. These boots are 100% sealed using O'Neill's exclusive fluid seams and is lined with a firewall interior. The boot features a multi density thin rubber sole that