Philips TUV TL Mini16W T5 Germicidal Fluorescent Light Bulb (9280 020 04013)TUV 16W FAM/10X25BOX*** UPC 8711500638694 is for 1 pc From PHILIPS ****** UPC 8711500638700 is for Carton with 25 pcs From PHILIPS ***TUV TL Mini lamps are slim double-ended UVC (germicidal) lamps used in residential water and air disinfection units. The small 16 mm diameter of the lamp allows for a small system design and design flexibility. TUV TL Mini lamps offer almost constant UV output over their complete lifetime, for maximum security of disinfection and high system efficacy