One advantage of fluorescent bulbs is that they last very long and therefore are cost-efficient. On this light bulb you'll find a 2G7 socket.
From Amazon
Osram 2G7 11 Watt Compact Fluorescent Light Dulux Lamp
LED Bulbs
Osram 11W Dulux S/E 4 PIN Warm White - OS589374
Big on Electricals
Osram 11W Dulux S/E 4 PIN Warm White - OS589374