The original X-Force was probably the fastest and quietest bow I've ever shot, truly a rare combination. It uses radically oriented (inward-arching), stubby split limbs and aggressive cams to produce incredible speed with little vibration. The only downfall was that it was not for beginners with its short brace height.
Archery mogul PSE comes back with a miniature X-Force called the X-Force Super Short. At 26 inches axle-to-axle, it is, to my knowledge, the smallest bow on the market by a major manufacturer; don't even think about shooting with fingers! Yet, by using the X-Force technology limbs and Hybrid Fast cam design, it is still ultra-fast. With a draw weight of 60 pounds at 26.75 inches, the bow shot a 349-grain arrow an average of 270.09 fps. through PSE's Phantom drop-away rest. This is fast! On Easton's Draw Force Mapper, these cams registered 65 pounds of stored energy for this 60-pound setup!
Again, surprisingly, it is also extremely quiet, the second-quietest of the four I tested. And, in shortening the bow, the brace height was made longer-it's now 7 inches-so it's more forgiving. I particularly like the simple, thin, exposed-frame grip, but this is personal preference.
The bow is so small and light, however, that I could notice movement in my bow hand while shooting, a flaw in shooting form that if left uncorrected can be detrimental to accuracy at long range. All in all, the X-Force SS is a specialized bow suited perfectly for a treestand, and it is a true marvel of modern archery advancements.