Nalgene™ Lined HDPE Serum Vial Closure for Continuous-Thread Vials:Nalgene Lined HDPE Serum Vial Closure for Continuous Thread Vials: Nonsterile Eliminate the need for a rubber stopper while maintaining a leakproof seal with these lined, HDPE serum vial closures, for use with continuous thread PETG serum vials. Closure Color: White Description: Serum vial closures Color: White Diameter (Metric) Outer: 22. 1 mm Sterility: Non sterile Liner Material: Three ply co extruded liner (LDPE core between two facing of solid