Made In USA. Melling expansion & freeze plugs provide an economical way to supply plug requirements to complete your engine rebuilds. Melling offers individual engine plugs or boxes of 10 or 25 for engine builders who require specific plugs in large quantities. Each individual plug or bulk pack contains high quality expansion/freeze plugs needed in specific dimensions to complete the job. Melling expansion/freeze plug are available in either steel or brass depending on engine usage and customer preference.