T5 Triphosphor Tubes Model Voltage (V) Wattage (W) Length (inches) Life (Hrs) Colour Temperature (K) #545 – T5 21W 4100K (F21T5) 110V-130V 21W 36″ 20,000 4100K #546 -T5 28W 4100K (F28T5) 110V-130V 28W 48″ 20,000 4100K