Science Equip Hollow Glass Stoppers are precision-crafted from Borosilicate 3.3 glass — the gold standard for laboratory glassware. Designed to seal flasks, columns, and vessels fitted with standard conical (NS) joints, these stoppers deliver reliable, leak-free performance across a wide range of laboratory applications.

•       Made from Borosilicate 3.3 glass — excellent thermal resistance and chemical inertness

•       Hexagonal plate for secure grip and easy handling

•       Flat bottom design for stable placement on bench surfaces

•       Precisely ground conical (NS) joint for an airtight, leak-free seal

•       Resistant to heat and almost all commonly used laboratory chemicals

•       Meets the highest quality standards for analytical and research laboratories

•       Available in a full range of NS joint sizes (7/16 to 60/46)

•       Packing: 1 Pc / Pack

•       Sealing round-bottom flasks, Erlenmeyer flasks, and distillation columns

•       Closing off ports on condensers and separating funnels

•       Used in organic chemistry, analytical chemistry, and biochemistry labs

•       Suitable for vacuum and pressure applications (within rated limits)

•       Ideal for university, school, and industrial research laboratories

Other sizes beyond the standard stocked range may be available on request. Contact the Science Equip team at www.scienceequip.com.au for availability, bulk pricing, and custom orders.

Sizes & SKU :

The following sizes are held in standard stock. All items sold individually (1 Pc/Pack).

The following sizes are available — please contact Science Equip for pricing and lead time.

How to Identify & Measure Your Joint Size

The NS (Norm Schliff) size designation is written as XX/YY, where:

•       XX = The widest diameter of the conical joint, measured in millimetres

•       YY = The nominal length of engagement (ground glass contact zone), in millimetres

•       Standard taper = 1:10 (the diameter decreases by 1 mm for every 10 mm of length)

•       Use callipers to measure the widest diameter of your vessel's ground glass socket — this is your XX value.

•       Measure the length of the tapered ground glass section — this is your YY value.

•       Match both values to the NS size designation in the SKU table above.

•       If unsure, contact the Science Equip team with your measurements for assistance.

Safety & Warnings

•       Safety glasses or goggles must be worn at all times when handling glass equipment.

•       Chemical-resistant gloves should be worn when handling glassware used with hazardous chemicals.

•       Wear a lab coat or protective clothing to protect against chemical spills and glass fragments.

•       Closed-toe shoes must be worn in the laboratory at all times.

•       NEVER use bare hands to pick up broken glass fragments. Borosilicate glass produces extremely sharp shards.

•       Use a dustpan and brush (dedicated to broken glass), tongs, or forceps to collect large pieces.

•       Use damp paper towels to collect fine glass fragments — never dry cloth.

•       Dispose of broken glass in a clearly labelled sharps/glass disposal container — never in a regular bin.

•       If chemical contamination is present, follow your institution's hazardous waste disposal procedures.

•       Report all glass breakage incidents as per your laboratory safety management plan.

•       Although Borosilicate 3.3 glass has excellent thermal resistance, sudden extreme temperature changes can cause cracking or shattering.

•       Never place cold glassware directly into a very hot environment, or pour hot liquids into cold glass vessels.

•       Allow glassware to cool gradually and uniformly before handling or placing on cold surfaces.

•       Inspect glassware for chips, cracks, or star fractures before each use — damaged glass is significantly more susceptible to thermal shock failure.

•       Do not use glassware beyond its rated temperature range.

Contact us: www.scienceequip.com.au