This light bulb has an A energy rating. On this light bulb you'll find a G5 socket.
From Amazon
Osram 54 Watt Lumilux T5 High Output Fluorescent Tube Lamps
Conrad Electronic
OSRAM Fluorescent tube EEC: G (A - G) G5 54 W Cool white Tube shape (Ø x L) 16 mm x 1149 mm 1 pc(s)