Features of the La Sportiva Synchro Boot Lightweight GrilamidA(R) shell provides rigidity without compromising weight Patented Carbon Reinforced GrilamidA(R) vertebra Technology delivers our stiffest boot to date at 125 flex Innovative hinged Double Power&rtrade; Tongue increases mobility and flex Pegasus Plus Buckle(TM) locking system consists of 4 Oversized buckles that Are easy to micro-adjust in the field New Overwrap UltralonA(R) foam liner provides improved warmth and comfort for charging downhill