RKS 4 ft. 118-Watt Equivalent Integrated LED White Magnetic Strip Retrofit Kit 5000K (4-Pack)Optilumen RKS Universal Fluorescent Fixture Retrofit Kit. Easily converts most all your existing residential and commercial 4 and 8 foot T5, T8 and T12 linear fluorescent light fixtures into an integrated LED light fixture. This retrofit kit works with the earliest to the latest versions of ceiling mount, four foot and eight foot fluorescent light fixtures, regardless of the style, manufacturer or existing ballast type including linear high bay, strip