The PANTHER SERIES Strike Punch Bag is made of a strong cross-fiber bonded synthetic material and features double-stitched seams for added strength. The size and 22mm foam lining provide an authentic feel when punched. The bag has heavy gauge metal D-rings for added durability and a heavy-duty zip that keeps the top securely closed and is protected by an additional flange of material to keep the zip hidden. The bag also has an additional metal D-ring at the base for attaching a fixing or weight to reduce swinging during heavy workouts. A 4 strand hanging chain set (sold separately) with a swivel fixing is required for proper use, to ensure more even bag wear.