Insulated socket sets protect against electrical shock from live electrical circuits and can be used to tighten and loosen fasteners near electrical components. They provide more contact to the fastener head than an open-end wrench and can apply more torque since the enclosed head is less likely to slip off the fastener. Sockets require the use of an insulated hand drive tool such as an insulated ratchet or breaker bar to turn the socket and rotate the fastener. Drive tools have a square nub called the drive that fits into the same size drive end of the socket for secure attachment to the drive tool. Sets come with an assortment of sockets for a range of fastener head sizes.