The LH0510 Leviton 23451-20 is a shunted lampholder/socket/tombstone. It is for G13 medium bipin base fluorescent tubes or LED lamps that specify a shunted lampholder/socket/tombstone. For fluorescent lamps that ballast needs to designated instant start. The Leviton 23451-20 easily slides for mounting and has quick wire connects for easy wiring. It is similar or equal to the Miller OEM L23451-20.