I'm always searching for my hex keys (or Allen wrench or Allen key) so mayby this will help.

Did you know in Finland we call hex keys "kuusiokolo", which translates to "six sides hole". Germans use the word "inbus", Italians call them "brugola" and swedes call them "unbrako". Now you know!

Biltema pegboard holes are 4mm wide and 12mm abart from each other and it is sold in Scandinavia, but there are other brands around the world with same diameters.