La Sportiva, K3 Mountain Boot All Climbing >>> Climbing by La Sportiva More details and ordering info. Featuring a silicone impregnated Full-Grain leather upper, a roomy toe box to accommodate thick socks and a 3M Thinsulate lining for added warmth, the K3 is an excellent boot for cold weather pursuits. Add a nylon, steel and carbon fiber insole and new EZ-Pull lacing system to make adjusting the fit a breeze and the K3 is unequalled in alpine climbing performance and comfort. User input on K3 Mountain Boot by La Sportiva: Be the first to submit input on this product Submit Input: Your Name: Write or Paste Input here: Upload picture:      Review Guidelines