RACO® is a leading manufacturer of steel electrical boxes, covers, and commercial fittings. One of the oldest brands in the electrical industry, our name is synonymous with quality and innovation. One of our innovative features found on our steel boxes are TKO Knockouts. TKO Knockouts offer greater flexibility with combination 1/2 in. and 3/4 in. knockouts. This feature is UL Listed providing bonding without the use of bonding jumpers.