Screw caps & closures

The cap must match the thread of the bottle or tube exactly. Laboratory bottles mostly use GL sizes such as GL 14, 18, 25, 32 and 45; the number is the outer thread diameter in millimetres. Tubes and vials often use a size in mm or an ND size. When a title says "for art. no." or "for cat.", the cap is made for that specific product series, as with the 12 mm screw cap with O-ring, green. A GL 45 example is the PP screw cap with seal, GL 45. Unsure? Send us your bottle at sales@luminixhealth.com.

An O-ring makes a screw cap leak-tight for storage, freezing and transport, as on the 12 mm screw cap with O-ring, 500 pieces per pack. A septum lets you take samples or inject with a needle without opening the vessel. Examples are the PP screw caps with integrated PTFE/silicone septum, 250 pieces and, for autosampler vials, the ND10 screw closures with hole and silicone/PTFE septum, 100 pieces. Without seal or septum, a cap is fine for routine storage. Vial caps are in vials, caps and septa.

Colours are mainly for coding: they help you tell samples, reagents or users apart at a glance, or follow a colour scheme in your lab. The 12 mm screw caps with O-ring come in several colours for that reason. Usually the colour makes no functional difference, unless the product page says otherwise. Sometimes it does: some coloured bottle caps belong to a heat-resistant version, such as the yellow PP screw cap, GL 45, which is heat-resistant up to 134 °C. So always check material and temperature on the product page.

PP is the standard for screw caps: chemically robust and often autoclavable. The PP screw cap with seal, GL 32 and its GL 45 version are autoclavable up to 121 °C, according to the product data. PE caps, such as the PE dropper cap, GL 14, are soft and suit dropping and dispensing; check their heat limit first. Septum caps have their own range; some silicone/PTFE septa are rated from −60 °C to +200 °C. Check the maximum temperature on each product page before you autoclave or heat. Questions: sales@luminixhealth.com.

A screw cap has a thread and a liner. The thread has to match the bottle. The liner has to survive the liquid: a pulp liner fails in a solvent that a PTFE-faced liner ignores. The colour of the cap is not the specification.

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.

This shelf belongs to Stoppers, caps & closures, inside Labware. Luminix Health distributes this range for laboratory use.

The neighbouring shelves are Rubber & silicone stoppers, Ground-joint glass stoppers, Lids & seals and Closures (other). The category above this shelf is Stoppers, caps & closures.

Luminix Health distributes this range from the heart of Europe. We deliver across the EU in two to five days if 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. Send a quote request, contact the team, or read who we are. The full brand index is on shop by brand.

The seven catalogues are Labware, Lab chemicals, Lab instruments, Lab consumables, Chromatography equipment, Lab safety equipment and Life Science & Microbiology. If the article is not on the shelf, request a quote.