Interlocks wide range of wedges work in conjunction with the window fasteners to ensure a tight seal between the window sash and the window frame. All conventional window fasteners require a wedge to be fitted to the window frame, providing a surface for the tongue of the window fastener to compress and seal for a watertight window. Features: - Rivet or pin fix options - Variety of thicknesses available - Manufactured from high quality nylon to provide a long life and low friction wedging action - Design options offer ease of installation along with neat appearance