2 mm neoprene, watertight stitched/taped assembly (GBS).
No palm reinforcements, so that you keep your sense of touch.
Thermal insulation and assembly features
2 mm neoprene. The seams of the gloves are waterproof due to GBS assembly (Glued and Blind Stitched): the neoprene is glued first of all, then sewn for maximum strength (the sewing needle does not go completely through the neoprene in order to prevent water infiltration).
Choose the right size
Try on your diving gloves. The tightest possible fit is required for optimal thermal insulation, like a second skin.