The SL is the 9th generation of the Scarpa classic. The SL Activ is one tough trekking boot, now even more luxurious and comfortable, while still being fully compatible with C1 walking crampons. The SL is now built on the latest TM last shape, giving an improved heel fit and closer fit across the forefoot. The redesigned upper uses a soft nubuck leather cuff with a cut out at the achilles, as well as redesigned flex zone, giving greater comfort on long descents and ascents in the mountains. The revised speed lacing system gives a sure hold across the instep, and the plush leather lining inside the boot is instantly luxurious and comfortable. The SL is built using Sherpa leather, the toughest and most water-resistant of any full grain leather Scarpa uses, impregnated with HS12 and built as a one piece construction for durable weather protection. The SL also uses the Vibram biometric trek sole for traction and support when carrying a large pack. The leather and 37.5 lining (and lack of membrane) all combine to make this a brilliant boot for warm weather trekking. Mens SL Activ Boots