Product Details Flex Soft Flex: 1 (1 Soft - 10 Stiff) – Soft flexing outsole and upper shell materials for ultimate learn to ride comfort. Liner Liner-Less with 3M™ Thinsulate™ Insulation – Mapped synthetic insulation materials that are extremely warm, lightweight, and bulk-free. Lacing System Dual Zone Shred Ready Hook-and-Loop Straps – Oversized and mitt friendly so kids can get their boots on, off, and adjusted without help from mom, dad, or the instructor. Footbed Room-To-Grow™ Footbed – To keep up with kids' constant growth spurts, the Room-To-Grow™ footbed allows you to gain one full size. Rather than buy new boots every season, simply remove the footbed when the fit becomes snug. A secondary, integrated footbed means there's no compromise in cushioning or support. Sole DynoLite Outsole with Size Indicator – Superior cushioning, improved board feel, and consistent support in a 20% lighter weight construction. Made entirely of an exclusive cushioning compound specially formulated to withstand repeated impacts and freezing temps for long lasting shock absorption. Soft-Flexing Outsole Additional Features Snow-Proof Internal Gusset – All Burton boot tongues feature an internal gusset construction to completely seal the lower zone of the boot, keeping your feet warm and dry.