Regular - with "legs" measuring approx 7/8"

These book corners have "legs" approximately 7/8" long.

The Brass, Nickel, Black and Brass Scalloped have channels measuring approximately 0.139" or 3.5mm Channel width of the Brass Engraved corners is approximately 0.115" or 2.9mm Channel width of the Copper with the cut out notch is approximately 0.065" or 1.65mm

Because the corners are crimped to the book cover, often the channel doesn't have to be "perfect".  There is often variation between batches of corners and that includes metal colour.