187 Killer Pads® Lock-In™ Core System - Removable foam allows for easy washing - Interlocking straps link foam to center of pad casing V-22™ Dual Density Foam - Specially formulated to provide the perfect combination of cushion and protection for multiple hard impacts Rapid F L E X™ Hinge - Allows pad to respond freely to full range of motion; straighten or bend leg with little or no resistance Fusion Groove™ Channel - Maintains foam connection to skater's leg and helps eliminate pad slip downs 187 Killer Pads® Lock-In™ Cap System - Secures and aligns removable cap in correct position Proven 187 Killer Pads® Design Elements - Light-weight fast drying interior lining - Seamless interior finish for ultimate comfort - Ballistic nylon with industrial-weight stitching ensures durability - Three-panel construction for reliable performance - Open back design for excellent fit and quick on & off 187 Killer Pads Pro Derby Knee Pad