4 in square junction box extenders allow the installer to raise the height of 4 in square electrical boxes 3/4 in to the desired finished surface. 4 in square mounting tabs match most electrical and electronic devices covers and plaster rings. They are often used to bridge the gap between a recessed box in the wall or ceiling and the finished surface level per the NEC electrical code. Bottom easy mount slots quickly attach to the existing box in the wall or ceiling.