$36.75 per fixture. Orders shipped only in quantities of two. Replace your traditional LED 4-foot, two-bulb fluorescent fixture with our 4-foot led strip retrofit kit. For 8-foot fixtures, two 4-foot retrofit kits can be installed end-to-end. All you have to do is remove the existing fluorescent lamps, the cover of the fixture, and the ballast. Disconnect the existing wires, attach the safety chain to the new 4-foot retrofit kit, connect the wires, and screw the retrofit strip into the interior case.