Plastic sash frame corners are designed to fit into square-cut ends of universal aluminum "C" sash frame material to repair or construct new frames. Square-cut assembly eliminates the need for miter cutting providing for an easier frame construction by the homeowner. These corners are designed for use with Prime-Lineft.s aluminum sash frame material which is constructed with pre-installed vinyl seals and factory installed pile weather-stripping. These components are used for constructing sash frames with single strength glass, double strength glass, or acrylic sheet material.