The Delta Activ Leather gets its name from the Activ Fit technologies that combine to make this beautiful boot so comfortable & capable. Four main elements, the BD last, the outer sole, ergonomic design & the footbed combine to give you a high performance boot that will be instantly comfortable & remain that way. Auto foam inserts in the heel mould to your body shape providing cushioned support & reduce heel lift eliminating blisters. The high tech sole unit combines biometrically designed sole pattern to aid a natural heel to toe transition whilst providing traction. Underfoot cushioning is maintained with dual density PU, & not just any ordinary PU, this stuff is produced in highly scientific environments to maintain the highest performance & quality standards. The thermo plastic (TPU) midsole give the Delta its internal strength & progressive flex. Topping off all this amazing technology is an upper made from the highest quality calf leather lined with soft calf leather for maximum breathability. If cared for correctly this combination of leathers will keep out virtually all water, but they are not guaranteed waterproof.