The Tandem In-Line Wiring option provides factory installed wiring when fixture sections are applied in pairs, and require left/right lamp switching. To explain, ballast receive their power from the circuit, with lamps getting their power from the ballast. TILW is the method of applying power from the ballast to specific lamps. TILW only applies to 2 or more lamp cross sections. If the luminaire has only one row of lamps, TILW is already present and unnecessary to specify. The TILW option is available on IA/IC, DI/DIM/DIVM, EI/EIM/EIVM, SS, SSL, SN, SNSM, SNRA, STN, STM, STW, RCG, P410, UT, I5 and BSX. Certain airborne contaminants can diminish the integrity of acrylic components. Refer to the Material Compatibility tables for additional information.