It would be cool if the selected bit area had some type of indication to the specific bit that was selected opposed to just the diameter. For example if the selected bit is an inventables bit a colored line could be added to the bottom that matches the ring color. As an example I have mocked up what it might look like if I have a 1/8in Dual Flute Straight bit (black ring) as my main bit and a 1/32in Spiral Downcut bit (pink ring):
Seeing the color there is just another confirmation that all my settings are correct.
(In case it helps I mocked this up by adding a border color to the anchor tags (#main-bit-link and #detail-bit-link)