Specifications

Hollow Stopper · Specifications

Standard sizes are listed below. All products comply with GB/T, ASTM, and ISO standard taper systems. Full range 10/19 ~ 60/45 available. Custom head types are available.

Request custom specs

1. Straight-Head Hollow Stopper

GB/T	ASTM	ISO	Overall Length (mm) approx.	Head Type	Material
Please contact us to confirm the available specifications.

2. Hex-Head Hollow Stopper

GB/T	ASTM	ISO	Head Type	Features	Material
Please contact us to confirm the available specifications.

3. Ball-Head Hollow Stopper

GB/T	ASTM	ISO	Head Type	Features	Material
Please contact us to confirm the available specifications.

* Joint numbers (10#, 14#) indicate the largest diameter (mm) of the taper. All are 1:10 taper.
* GB/ASTM/ISO designations are different standard identifiers — physical dimensions are identical and fully interchangeable.
* Full range 10/19 ~ 60/45 available upon request.
* Flat-head stoppers available for space‑limited setups.
* Lengths are approximate and may vary slightly.
* Contact our sales team for MOQ and lead time on custom orders.

✦ Customization Services — We offer custom joint sizes and head types. Share your specific requirements and our technical team will provide a tailored solution.

Product Description

The hollow stopper is a fundamental accessory for temporarily sealing standard taper joints in standard taper glassware systems. Its hollow construction makes it lighter than solid stoppers, and the hollow channel can accommodate gas inlet tubes for gas introduction or evacuation when needed.

Available in straight, hex, ball, and flat head configurations, these stoppers accommodate different handling preferences and application requirements. Precision-ground 1:10 taper joints ensure reliable sealing with all standard joint glassware, effectively preventing gas leakage and liquid evaporation while maintaining system integrity.

Key Features

Borosilicate Glass 3.3: Meets ISO 3585, low thermal expansion, thermal shock resistance up to 280°C, excellent chemical durability
Multi‑Standard Compliance: Precision‑ground 1:10 taper meets GB/T, ASTM E, and ISO 3585 standard taper specifications for full interchangeability
Hollow Construction: Lighter than solid stoppers; can accommodate gas inlet tubes for gas introduction
Multiple Head Types: Straight (standard, most common), Hex (easy hand-tightening), Ball (comfortable grip), Flat (space-saving)
Reliable Sealing: Effectively prevents gas leakage and liquid evaporation, maintaining system integrity
Durable: Glass construction withstands temperature changes and chemical exposure

Quality Assurance

Each hollow stopper is inspected for taper accuracy and surface finish to ensure reliable sealing with all standard joint components. Custom bulk orders are welcome.

Tip: Ensure joints are clean and dry before insertion. Insert with a gentle twisting motion. For gas introduction, use with a gas inlet tube through the hollow channel.

Applications

Typical Uses

Sealing Reaction Vessels

Seal flasks, test tubes, and reaction vessels in organic and inorganic synthesis

Temporary Sealing

Temporarily seal standard joints during experiments to prevent contamination

Biological Experiments

Seal culture flasks and vessels to prevent contamination

Gas Line Connections

Hollow construction allows gas introduction or evacuation with gas inlet tubes

Apparatus Protection

Seal standard joints to protect ground surfaces when not in use

Compatible Equipment

Standard joint flasks, test tubes, reaction tubes

Three-neck and four-neck flasks

Condensers, distillation heads

Culture flasks, reagent bottles

Tip: Always use matching standard joint sizes for optimal sealing. Hollow stoppers can be used with gas inlet tubes for gas introduction or evacuation.

Operation & Maintenance

User Guide

Before Use

Inspect for cracks, chips, or scratches on the joint
Clean the joint surface with a soft cloth to remove particulates
Confirm that the joint size matches your apparatus

Insertion

Align the stopper joint with the apparatus joint
Insert with a gentle twisting motion to ensure a tight fit
Hex-head stoppers can be tightened by hand using the hex grip
Avoid excessive force to prevent glass breakage

Removal

Remove with a gentle twisting motion
If stuck, use a heat gun to gently warm the outer joint
Clean joints immediately after removal

Cleaning & Storage

Clean immediately after use to prevent residue buildup
Use soft brushes and appropriate detergents for the joint and hollow interior
Air dry and store with protective paper between ground joints
Protect joints from impacts

Hollow Stopper · Selection Guide

Three key dimensions determine the right hollow stopper for your system: head type, joint size, and application.

1. By Head Type

Head Type	Features	Typical Use
Please contact us to confirm the available specifications.

2. By Joint Size

Scale	GB/T	Typical Volume	Matching Apparatus
Please contact us to confirm the available specifications.

3. Quick Selection Checklist

Follow this decision flow to quickly identify the right configuration:

① Frequent insertion/removal? No → Straight | Yes → Hex
② Comfort grip important? No → Straight | Yes → Ball
③ Space limited? No → Straight | Yes → Flat
④ Scale? Micro → 10#/14# | Standard → 19#/24# | Large → 29#+

✦ Need help selecting? Contact our technical support team with your apparatus specifications and application requirements — we'll recommend the optimal configuration.

Care & Notes

Show care & notes

Safety Precautions

Observe temperature limits during high-temperature operations
When introducing toxic gases, always operate in a fume hood
Wear protective gloves and safety goggles

Do not

Never use cracked or damaged stoppers