The SafeGrip Belt Clamp is a unique, versatile locking clip. It locks the lap portion of your lap & sash seat belt in place, preventing slack in the seatbelt. As a result, this ensures a firm installation when used with a child restraint with an in-built harness. When used with a Booster Seat, the Belt Clamp locks the lap seat belt. This enhances the Booster Seat’s anti-submarining features.