Volumetric Flasks Clear Glass With Hollow glass Stopper Class-B
Product Code : EL-VF-10278
Lab Glassware Manufacturer produces the Volumetric Flasks Clear Glass With Hollow Glass Stopper Class-B at its manufacturing facility in Ambala, Haryana, supplying school, college and research laboratories across India and exporting to institutional and distributor buyers in Kazakhstan, Uzbekistan and Turkmenistan and other markets across Central Asia.
Quick answer: This is a clear (non-amber) borosilicate glass volumetric flask sealed with a matched hollow glass stopper rather than a solid glass, PE or PTFE stopper, made to Class-B tolerance. The hollow stopper is ground to the same interchangeable neck size as the flask it is supplied with, giving a snug, chemically inert glass-on-glass seal without the added weight of a solid glass plug. It is available across 13 capacity/neck-size combinations from 5 ml to 2000 ml.
| Capacity (ml) | Neck Size (N/S) | Tolerance (± ml) |
|---|---|---|
| 5 | 10/19 | 0.080 |
| 10 | 10/19 | 0.080 |
| 20 | 10/19 | 0.080 |
| 25 | 10/19 | 0.080 |
| 50 | 12/21 | 0.120 |
| 50 | 14/23 | 0.200 |
| 100 | 12/21 | 0.200 |
| 100 | 14/23 | 0.200 |
| 200 | 14/23 | 0.300 |
| 250 | 14/23 | 0.300 |
| 500 | 19/26 | 0.500 |
| 1000 | 24/29 | 0.800 |
| 2000 | 29/32 | 1.200 |
Why Choose a Hollow Glass Stopper Over a Solid or Polymer Stopper
A hollow glass stopper is ground on a hollow (lightened) glass blank rather than a solid one, so it seals with the same chemical inertness and thermal stability as a solid glass stopper while being noticeably lighter in the hand — a small but real difference on repeated shake-and-mix titration or dilution work. Because the stopper is glass-on-glass ground to the flask's own neck, it resists staining and swelling from organic solvents that can gradually cloud or grip a PE or PTFE stopper over years of use, though the interchangeable ground joint should still be lightly greased or lapped periodically to keep it turning freely. Class-B tolerance on this range makes it a routine-use, cost-effective specification: schools, colleges and general QC benches that do not need Class-A/serialized certification get full functional accuracy at a lower price point than a certified flask.
Frequently Asked Questions
What does "hollow glass stopper" mean, and how is it different from a solid glass stopper?
A hollow glass stopper is blown or ground from a lightened, hollow glass blank instead of a solid glass rod, so it weighs less than a solid stopper while still forming the same ground glass-to-glass seal at the flask's interchangeable neck. Functionally it seals and performs the same as a solid stopper; the difference is weight and, for some users, feel in the hand.
Why is this flask offered in Class-B tolerance rather than Class-A?
Class-B is the standard, wider tolerance band suited to routine teaching, general dilution and non-certified laboratory work, and is priced accordingly. Where a tender or analytical method specifically calls for certified, serialized Class-A accuracy, ask about the Class-A equivalents in this range instead.
Is the stopper interchangeable with other flasks of the same neck size?
The ground glass joint follows standard interchangeable neck sizes (for example 10/19, 14/23, 19/26), so a stopper of the same marked size will generally fit another flask of that size, though for volumetric accuracy each flask should be used with its own matched, factory-paired stopper wherever possible.
Can this flask be supplied for bulk, tender or export orders?
Yes. It is supplied in bulk to schools, colleges and laboratories in India and is exported to distributor and institutional buyers, including recent enquiries from Central Asian markets such as Kazakhstan, Uzbekistan and Turkmenistan. Share capacity, quantity and destination country through Contact Us or the Tenders page for a quotation.
Related Products
Explore other Volumetric Flasks: Volumetric Flasks Clear Glass with PE Stopper Class-B and Volumetric Flask With Snap Cap, Unserialized Class-A, or see the full Volumetric Flasks range.
Request a Quote
Ready to order Volumetric Flasks Clear Glass With Hollow Glass Stopper Class-B for your laboratory, institution or export order? Contact Us for a quotation, or visit the Tenders page for bulk and institutional procurement.
Last updated: September 2026.