30MT - Tapered shaft out both sides. Tapers from 3/4" to 5/8" over 1.5".   Fits into the F-3 Tapered fork for the Space Saver. Shaft and bearing are pressed directly into the solid aluminum core of a small rubber wheel.

30ML - Straight 5/8 " diameter shaft out of both sides. Fits into the F-3 Lock-In fork for the Space Saver. Shaft and bearing are pressed directly into the solid aluminum core of a small rubber wheel.