Polypropylene, Wadless, Screw Closures are the most cost effective method of sealing Screw-necked Bottles or Jars. The sealing-rim inside the Cap provdes a flexible seal to the top surface of the Neck of the container. This one-piece Closure has been well proven to perform consistently. The 33mm and 38mm sizes offer the added option of a Tamper-evidence feature, provided by a Pressure-sensitive ‘sticky’ Wad which adheres to the neck of the Container as the Closure is screwed on.