Nalgene® Serum Vial Closures, HDPE, Thermo Scientific. Supplier: Thermo Fisher Scientific. Description: These 20mm, high-density polyethylene screw cap closures are available lined or unlined and sterile or nonsterile. Certificates. ,73520-090CS,73520-096CS,16060-100CS,16059-992CS,73520-092CS,73520-094CS.