The shank of the instrument mounted therein is 2.35 mm. The pedal only functions as a switch and cannot be adjusted. Dental micro motor marathon polisher machine &35k rpm handpiece with10 drills burs this item can be shipped to united states. We try our best to reply to your emails as soon as possible, however, due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately.