Allows the contractor to comply with 2005 NEC Article 314 20 * Works in handy boxes and 4 Inch square electrical boxes with plaster rings for single switches or receptacle * Manufactured from 105 degree C continuous use 94VO rated flame retardant plastic for safer installations * Functions with all standard devices Switches, and GFCIs * Levels and supports the wiring device where the box is set back from the wall surface (adjusts up to a 1-1/2 Inch box extension)