The GP Pro R4 is the heir to a long line of Alpinestars race gauntlets, built on their full-grain kangaroo and goatskin palm with hard knuckle armor, double-layered finger reinforcements, and a rigid scaphoid slider on the heel of the hand. It's CE Level 2 certified — the higher of the two ratings — and the shape is aggressive enough that most riders need a break-in period before the curved fingers stop feeling locked into a riding position.
What riders consistently report: the glove disappears at speed. Wind doesn't get into the gauntlet, the slider on the palm has been redesigned to actually pivot on impact instead of grabbing pavement, and the touchscreen-compatible fingertip on the index finger works often enough to count.
On the downside: this is not a casual canyon glove. The double-stitched finger sidewalls are stiff, the gauntlet is tall enough to fight a textile jacket sleeve, and the price is squarely in track-glove territory. If you're commuting daily, the SP-X or SP-8 V3 in the Alpinestars lineup will treat your hands better.
How it compares: against the Dainese Carbon 4 Long (the obvious rival), the R4 is a touch stiffer out of the box, slightly better-ventilated in stop-and-go, and arguably better protected at the scaphoid. The Dainese wins on finger feel right away; the Alpinestars wins after a couple of track days.