Glazelock interlocking plastic horseshoe shims are commonly used in the building industry and eliminate common issues of rotting, shrinking and swelling when compared to traditional wooden shims. These high quality plastic interlocking shims were invented by a window installer to simplify the use of multiple shim applications when installing windows. Glazelock shims reduce material and labor costs and provide a secure and stable solution for your projects that require shims. These shims can also be used when installing cabinets and leveling furniture and appliances. They also eliminate the need to glue or tape several shims together, provide easier placement with their collapsable locking mechanism and, being plastic, our shims are resistant to moisture and won't rot like the wooden ones.