BF Style Bits can be used with either a B Style shank / saw or an F Style shank / saw. These bits are a "double circle" design. This design disperses the cutting force along the entire length of the bit, as opposed to focusing the force on the "heel" of the bit as with 2-1/2, 3 and 33 style configurations. Consequently, the B and F Style saws are less prone to saw shoulder breakage. Regular and Long type bits can be used with Regular, Super or Wintar style shanks. Many sawyers find the long type bit does not run as smooth as a Regular type bit until after is has been sharpened a few times. This owes to the longer swage taking a larger bite while it is new. The Long Swage originated in the Pacific Northwest and was commonly used in the large softwood processed there decades ago. Use of a Long type bit in hardwood applications requires some measure of care when the bit is new. Standall and Dominator type bits should only be used with Regular style shanks.