The Delta Activ GTX 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 design 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 Gore-Tex for total belt & braces waterproofing.