Fluorescent bulbs have an advantage in that they are more energy-efficient than conventional bulbs. The socket on this bulb is a so-called G13 socket.
From Amazon
Osram Lumilux T8, Fluorescent Lamps, sockets G13L 58 W/865
LED Bulbs
Osram 58W T8 Fluorescent Tube 1500mm 5FT Daylight - 517933
Big on Electricals
Osram 58W T8 Fluorescent Tube 1500mm 5FT Daylight - 517933
Conrad Electronic
OSRAM Fluorescent tube EEC: G (A - G) G13 58 W Daylight white Tube shape (Ø x L) 26 mm x 1514.2 mm 1 pc(s)