For use on pendants, this lampholder is shade compatible (lock ring included) and takes 1 x BC / B22 lamp. Its dimensions are as follows: height - 57mm, width including shade ring - 32mm, and width excluding shade ring - 26.5mm. It embodies the essence of Britishness when it comes to a lampholder. What a light geek statement; however, if you are a purist or otherwise and want a bulb holder that will outlast all others, look no further than this version.