PSI has both prairie rattlesnake and diamondback rattlesnake blanks in 7mm, 8mm, 3/8", and 10mm. They are all 3/4" x 5", so you have to cut to your preferred length and square the ends; and they are a bit "pricey", but you can save a couple bucks on each blank by ordering from Woodturningz. They (PSI) are the only ones I know that have 7mm snakes, though you might also check Hut Products--can't recall whether they have them or not. Hope this helps!