HMK Voyager Boa Boots (Orange, 6) Feature the Boa closure system Boa closure system provides custom comfort with smooth, even closure and no pressure points that once locked into place with Boa reels and laces will stay that way; yet can be easily adjusted with one hand (even with gloves) including on-the-fly Lightweight Boa system is always quick/ easy on and off for these boots Full grain leather uppers Impervious to water and wind with a patented Sympatex breathable membrane; a non-porous membrane that unlike micro-porous materials, will never clog with dirt, detergent or other residues