5x Bell 13w T5 21 inch Fluorescent tube 640 4000k cool white light 13 Watt 530mm | eBay
10 x 21" 13W T5 Fluorescent Tube 535 [3500k] Standard White (Bell 05411) - - Amazon.com
30 x 21" 13w T5 Fluorescent Tube 535 [3500k] Standard White (Bell 05411) - - Amazon.com
Lightwise LWL7W40-F13T5 21" Direct Replacement Led Tube, 7-Watt, White, 4000K, Retrofit 13W T5 Fluorescent Tube of your Uncder-Cabinet Lights 50% Energy Saving, Replace Directly Set of 3