Cementing plugs are manufactured of graded rubber that is fused upon a composite or Aluminum core. >>This top plug can be used when dual plug system is not required and Bottom cementing plug can be used when dual plug system is required. >>These plugs are completely PDC drillable. >>Operating range of temperature with Aluminum core is up to 200 degree Fahrenheit.>>Plug can be ordered for higher operating temperature and operation in either synthetic or mud fluids.>>Available in 4 1/2" to 20 "sizes + any special sizes.