Pack of 5 Fluorescent Tubes T5 525mm 21 inches Cool White 4000k 13W : Amazon.co.uk
13W Fluorescent Tube-5-413-20
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Fluorescent-lamp formats - Wikipedia
Pack of 5 Fluorescent Tubes T5 525mm 21 inches Cool White 4000k 13W : Amazon.co.uk
5 Foot T5 Fluorescent Tube 49W G5 4000K Cool White - John Cribb & Sons Ltd, UK Electrical Distributors, Dorset, Hampshire, Wiltshire, Somerset & the Isle of Wight.