GE 13-Watt 21-in Miniature Bi-pin (T5) 4100 K Cool White Fluorescent Light Bulb in the Fluorescent Light Bulbs department at Lowes.com
F13T5WW – T5 21 Inch Under Counter Fluorescent Bulbs Warm White 3000K 13-Watt F13T5/WW 21” WW Long Life Replacement Tubes for Under Cabinet Lights – Pack of 6 Bulbs - - Amazon.com
6 Pack) F13T5/WW - T5 Fluorescent 3000K Warm White - 21" Linear - 13 Watt T5 - Under The Counter Light Bulbs - - Amazon.com