Features:

5 backs: 0.683, 0.686, 0.689, 0.692, 0.695
Tolerance stack : 0.0007 of an inch of bore indicated
Micro hone finish tolerance: 2 to 5 microns.
30 degree angel venting, clears broken paint out and away, no more drips throwing off shot after shot as happens in straight porting
Packaged in a gear bag and airport friendly protective tube.
Backs are optimized 6 inch length (its a good size)