This is a Goodyear-welted product. The upper and sole are heat-sealed and sewn together, not merely glued like many footwear constructions.
A smooth, slightly snuffed analine leather that has a special coating that imparts a significant waxy / oily feel.
This sole is hard-wearing, with good abrasion and slip resistance.
[Greasy] = Wipe away Dirt with damp cloth, ensure shoes are dry then apply proprietary Silicone or waxed product designed for waxy oily leathers - such as Dr Martens Wonder Balsam.