I have a 2009 Mazda 2 Sport. Recently passengers side headlight bulb has blown. I went to Halfords and bought the correct bulb, a "477SB H7" 12V, 55W Super Brilliance.
I then went to fit the new bulb and noticed the old bulb was significantly larger. It is stamped with "H4 12V60/55W (E8) 3G6".
I then looked at the drivers side bulb and saw that it had the smaller bulb, like the new one I just bought. However it seemed to have some kind of adaptor:
What is this adaptor that I am missing from my passengers side?