Rigid Industries New R36 Line Fits Into Standard PAR36 Bulb Enclosure. Rigid is expanding their round light line. Turn Square into Round with Rigid Industries expands its circular light offering with the all-new R-Series 36 Retrofit which has all of the superior output and technology Rigid is known for. This adaptive crossover sets itself apart from the rest with its curved lens, curved housing, compact design, optics and advanced heat sink. The R-Series 36 works perfectly as a drop-in replacement for a PAR36, as a spotlight, or wherever you need extreme light output. Available in Spot, Hyperspot, Flood, Diffused and Driving beam patterns, the R-Series 36 is the total lighting solution.