T5 Triphosphor Tubes ModelVoltage (V)Wattage (W)Length (inches) Life (Hrs)Colour Temperature (K) #545 – T5 21W 4100K (F21T5)110V-130V21W 36″20,0004100K#546 -T5 28W 4100K (F28T5)110V-130V28W 48″20,0004100K