Philips TUV 20W 4P SE UNP Germicidal Light Bulb (9279 734 04099)TUV 20W 4P SE UNP/32*** UPC 8727900815597 is for Carton with 32 pc From PHILIPS ***TUV T5 lamps are single- or double-ended UVC (germicidal) lamps used in professional water and air disinfection units. The small 16 mm diameter of the lamp allows for a small system design and design flexibility. TUV T5 lamps offer constant UV output over their complete lifetime, for maximum security of disinfection and high system efficacy.