Description
Polyethylene stopper NS 12/21 is an octagonal laboratory stopper intended for standard ground joints according to DIN 12254. Produced in PE-HD, it seals NS 12/21 sockets on flasks, bottles and related glass apparatus commonly found in chemical and analytical laboratories. The eight-sided head improves handling and torque when seating or removing the stopper, while the polyethylene body offers a lightweight, breakage-resistant alternative to glass. Net weight is 0,002 kg, keeping the component easy to manage in routine workflows. Available as a single piece from manufacturer Witeg, the stopper conforms to the dimensional conventions of DIN 12254 for interchangeable norm-ground joints. Low-density polyethylene material provides the chemical resistance expected for everyday laboratory use. Suitable for research, quality-control and teaching environments, it delivers reliable closure of NS 12/21 joints without the fragility of glass stoppers and supports economical replacement stock for busy lab benches.
This article is part of Ground-joint glass stoppers, in Stoppers, caps & closures.
Key features
- Pack size: 1 pc
- Joint size: NS 12/21
- Material: Low-density polyethylene (LDPE)
- Design: Octagonal
- Standard: DIN 12254
Recently viewed
You may also like
Browse related categories
Category
Sub-category
Catalogue
Brand
Questions about Polyethylene-stopper ST 12/21
What is this article?
Polyethylene-stopper ST 12/21 is the article on this page. Luminix Health distributes Witeg for laboratory use. It sits in Ground-joint glass stoppers, inside Stoppers, caps & closures, in Labware.
A ground-glass stopper matches a ground neck of a stated joint size. A 14/23 stopper does not seal a 29/32 neck. The stopper is part of the flask's seal, and a chip on the grind is a leak.
A closure is the part that decides whether a bottle stays shut and whether the contents attack the seal. A ground-glass stopper matches a ground neck. A screw cap needs the right thread and a liner that survives the liquid. Rubber and silicone stoppers push into a mouth. The liner, not the colour of the cap, is the chemical choice. The vessels they close are indexed under ISO laboratory glassware.
Which category should I open next?
The category is Stoppers, caps & closures. The sub-category is Ground-joint glass stoppers. The catalogue is Labware.
Shelves beside this one are Screw caps & closures, Rubber & silicone stoppers, Lids & seals and Closures (other).
What should I check before I order?
When this page shows a safety data sheet, use that manufacturer file. Hazard text does not belong in the sales description. For a pack size, a grade or a certificate that is not on the page, send a quote request or contact the team.
How does ordering and shipping work?
Luminix Health distributes this article from the heart of Europe. Articles in stock ship within 2–5 business days. Standard delivery is free from €250 excl. VAT. Cold-chain goods and dangerous goods under ADR are never included in that free delivery. The terms are in the Shipping Policy. The full brand index is on shop by brand. Who we are is on about us.
Which other categories should I open?
The seven catalogues are Labware, Lab chemicals, Lab instruments, Lab consumables, Chromatography equipment, Lab safety equipment and Life Science & Microbiology.