A no. 5-1/4 jack typically is shorter and narrower than a standard no. 5, but this innovative model maintains the 2" blade width. So it has the mass and feel of a no. 5, but with better balance.
…
And the proprietary PM-V11-steel blade (our model, 05P24.71, costs $242) held a sharp edge longer than any other jack in our test. To close up the mouth for tighter shavings, you move the entire blade-frog-and-handle assembly forward and back. (The included instructions make this easy.) And although the Norris blade-depth adjuster proved fussy at times, setscrews near the mouth restrict side-to-side blade movement.