Features 1) Shure URT2 Universal Rack Tray 2) The URT2 has pre-drilled holes for fasteners to secure the following Shure receivers: PG4; PG88; PGX4; PGXD4; BLX4; BLX88; GLXD4 3) If the URT2 will be used with older Shure receivers, the recommended fastening mounting material is self-adhering Velcro.