Existing modelZamberlan's most acclaimed alpine boot, the 4041 Expert Pro GT RR is designed for high level mountaineering and use on routes to glaciers. Lasted for a precise fit, the boot is constructed to provide maximum sensitivity and great performance. A double-tongue allows the user to customize their fit: push the tongue down and let the velcro and lace system provide a secure lower-volume fit; pull the tongue up and give yourself a higher volume fit. The Gore-Tex Duratherm lining and 3.0mm thick single Hydrobloc infused Swiss Perwanger leather upper combine to ensure warmth and durability to minus 20 degrees Celsius. The Expert Pro features a newly designed Vibram Teton sole that works in conjunction with Zamberlan's P.C.S. (Professional Crampon System). The Carbon Flex midsole makes the boot stiff and stable. The exclusive Zamberlan® R.R.S. protective rand helps prolong the life of the boot and offers improved protection for the foot. Available in Acid Green.