All specialty shoe stores have one and it is great for doing a quick check if your shoe is fitting properly or if there is an obvious problem in sizing that can be corrected. It became famous after it revolutionized shoe fitting for the Navy and lead to a massive decrease in foot pain.
It gives 3 measurements
How to measure how wide your foot is with the brannock device.
1)Put your right foot against the heel cup that says right foot. Press your weight down onto the device equally distributed between both feet. The foot length can then be calculated on -either the women’s or the men’s side, remember to measure to the end of the big toe and always round up by half a size if there is any confusion.
2)Move the arch pointer with its groove(located on the inside of your foot) to fit against the bump at the beginning of your big toe joint. This is the arch length.
3)Compare the sizes from step 1 and step 2: the larger number between the arch length(2) and the foot length(1) is your actual shoe size. This takes into consideration some people with a short arch but long toes and people with long toes and a shorter arch.
4)Press the width measuring device on the outside of your foot(side of the 5th toe) against your foot. Line the shoe size number from step 3 and line it up with the width letter. A is the more narrow width and E is a wider width. with B,C, D being in between. This is how to measure how wide your foot is.
Additional pearls for how to measure wide feet: