Description
Threaded stopcock retainer N NS 21,5 is a laboratory accessory designed to secure hollow stopcock plugs in ground-joint glassware assemblies. This Type N retainer fits NS 21,5 joints and is made from PE-HD; the set includes a screw cap, washer and O-ring for dependable fixation of the hollow plug. By locking the stopcock in position, it reduces the risk of accidental opening or loosening during stirring, vacuum operations or everyday handling, supporting safer and more reproducible laboratory work. The retainer from manufacturer Witeg is intended for use with matching stopcocks and jointed apparatus in research, teaching and industrial quality-control laboratories. Lightweight PE-HD construction—net weight approximately 0,004 kg—combines ease of installation with suitable chemical resistance for many routine laboratory applications. The component is simple to fit or replace as part of regular glassware care and helps maintain secure hollow-plug connections without damaging the glass. Supplied as a single piece, it is a practical addition to any laboratory that relies on stable stopcock performance in analytical and preparative setups.
This article is part of Stopcocks & valves, in Tubing, hoses & fittings.
Key features
- Pack size: 1 pc
- Type: N
- Joint size: NS 21,5
- Material: PE-HD
- For: hollow plugs
- Components: screw cap, washer, O-ring
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Questions about Screw-thread retaining nut ''N'' ST21,5
What is this article?
Screw-thread retaining nut ''N'' ST21,5 is the article on this page. Luminix Health distributes Witeg for laboratory use. It sits in Hose connectors, adapters & fittings, inside Tubing, hoses & fittings, in Labware.
A hose connector or adapter joins two lines, or steps one bore down to another. The barb diameter has to match the tube, and the thread has to match the stopcock or the bottle. Most leaks are a mismatch here, not a hole in the tube.
Tubing is how a liquid or a gas moves between two vessels without being poured. Silicone stays flexible and survives repeated autoclaving. PTFE resists almost every solvent and is stiff. PVC is the ordinary flexible line for water and for mild aqueous work. The fitting, not the tube, is what usually leaks: the barb, the thread and the stopcock have to match the tube bore. Glass and plastic apparatus around these lines is indexed under ISO laboratory ware.
Which category should I open next?
The category is Tubing, hoses & fittings. The sub-category is Hose connectors, adapters & fittings. The catalogue is Labware.
Shelves beside this one are PVC, PTFE & other tubing, Stopcocks & valves, Silicone tubing and Tubing accessories.
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. Delivery across Europe, two to five days when in stock. 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.