What am I?

Another late blip and back blipped...

Busy day at work followed with badminton and then a meeting with the Basingstoke Transition team followed by a CafeSci meeting on rocketry!

Can you identify the plug in the picture? It was introduced in 1987 and it's replacment was introduced in 1999. Even though they have been obsolete for ages they are still very common, and this one is going to be used used for something. I would expect many blippers to have one at home.