Philips 13-Watt 21 in. Linear T5 Fluorescent Tube Light Bulb Cool White (4100K) (1-Pack) 546499 - The Home Depot
F13T5CW – T5 21 Inch Under Counter Fluorescent Bulbs Cool White 4100K 13-Watt F13T5/CW 21” CW Long Life Replacement Tubes for Under Cabinet Lights – Pack of 6 Bulbs - Amazon.com
13W 21" Linear T5 Pre-Heat Fluorescent Lamp Daylight