I just had a set of Grafton Spped Controllers arrive at the office
However they are different to my others :?
I have two pairs - like the purple here with 3 holes and then these red ones with a slot instead of holes. Can anybody shed any light on this?

However they are different to my others :?
I have two pairs - like the purple here with 3 holes and then these red ones with a slot instead of holes. Can anybody shed any light on this?