Goodyear welt is a shoe construction technique used in the manufacturing of footwear with stitched soles. This construction method uses a narrow strip of leather called welt which is first sewn to the upper and inner sole of the shoe, then stitched to the outsole creating a stronger bond between the parts. Goodyear welt construction allows multiple sole replacements as well as better air flow through the shoe.
About Leather:
The skin of an animal that is tanned and used in shoes, bags, and other accessories.