The Tengu GTX by Aku is a crampon-compliant mountain boot that is waterproof thanks to its Gore-Tex lining. The boot offers a combination of a grippy Vibram sole and Aku exoskeleton midsole, which provides stability for normal trekking and hiking as well as climbing passages and enables precise stepping. The upper material is a mixture of polyamide, suede and Air8000+. The all-round protective rubber rand and protective toe cap provide all-round protection.