Hand sewn PVC synthetic cover. Latex bladder with two cotton windings and one polyurethane winding. Rugby Ball Inflating Instructions Moisten the needle before inserting. Use Glycerin or Vegetable oil.ĘThis seals the area around the valve, while saliva does not. Push the needle carefully into valve. Do not push the needle against the other side of the ball as this can puncture the bladder. Inflate to 9 10 PSI All natural latex bladders will deflate over a period of time. Always inflate before use.