-The YKK X-type 2 way zipper allows easy dressing and fast undressing. This long john also features A-symmetric cut on ankles for easier donning, less tearing and therefore more durability.his long john is made with 3 mm double lined neoprene. The back of the long john is made with abrasion and tear resident duratex neoprene.eatures:- duratex reinforces on the seat;- A-symmetric cut on ankles;- YKK X-type 2 way zipper;- big character sizing.