SUNLITE 13W 21 inch Cool White 4100K Fluorescent Tube Bulb - F13T5/CW - Walmart.com
4 Pack of 8W/21" T5 LED Tubes Replace 13W Fluorescent Tube for Undercabinet Lights Directly to get Over 50% Energy Saving and 50K Hours Life - Amazon.com
13W 21" T5 Fluorescent Tube White Lamp Series 517mm (exc Pins) Cabinet, Pelmet | eBay
Connectable T5 13W LED link light, opaque diffuser, cool white and warm white light
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