The outer shell is cut from full-grain leather rather than PU, which costs more per pair but resists cracking at the knuckle flex point far longer under daily gym rotation. Underneath, layered foam density is graded — firmer at the striking surface, softer around the wrist — so the glove protects the wearer's hand as much as the target.
10oz and 12oz pairs are what most commercial gyms stock for general sparring and bag work, while 14oz and 16oz are ordered by academies running dedicated sparring classes where extra cushioning matters more than speed.
Leather gloves should never be left damp inside a closed bag after a session — wipe the interior and let them air out, or the foam padding starts to break down and the leather stiffens unevenly.