PP, white. Mit TPE gasket. All-plastic closures for aseptic liquid transfer of media, biological reagents, pure water and chemicals to and from carboys. Used in applications requiring bi-reactors and fermenters. Can be used with any large Nalgene® carboys that accept 53 or 83 mm closures. Including two pieces platinum-cured silicone tubing for aspiration, dispensing and filling splash guards. Can be used with Nalgene® carboys with a properly set up peristaltic pump.