Tailored equipment in a few quick and incomplex steps: with easily combinable screw joint elements from BOLA you can flexibly react to all current requirements.



Chemical resistance       :              +++ universal

Material                         :              PPS

Temperature resistance  :              from -20°C to +230°C



Screw cap with handy knurl, with integrated PTFE/silicone gasket, suitable for GL threads, made of PPS. After assembly, the product is only exposed to PTFE.


For closing bottles and vessels with GL threads. (For thread GL 14, 18, 25, 32, 45)


Choosing a suitable fitting, screw cap or multiple distributor with the correct thread type and size is not as easy as it might seem with regards to the multitude of thread types.

On the following pages we have summarized the most common threads that we use at BOLA for our fittings, screw caps and multiple distributors.

Please use a sliding calliper for the determination of a thread type. Use it for the determination of the thread O. D. and the thread pitch. The pitch is the distance from one thread crest to the other as shown on our schematic drawings. Now the thread type can be determined by comparing the original thread with our figures. Once you have found a similar type, the actual thread size is identified by comparing the measured dimensions (thread O. D. and pitch) with the typical dimensions stated in the related chart.

Of course we will help you if you should still have problems in determining your thread. Just send us a sample or counter piece, we will be glad to help you with your choice. But please understand that we are not able to determine threads on faxed or scanned copies or pictures.




A distribution system consists of tubes or tubing and connection pieces, so-called tube fittings. The BOLA-GL-Fitting-System is a modular system which consists of tube fittings, screw-in fittings, different stopcocks and valves.

All fittings have GL threads so that they can be connected to hard-walled tubing (PTFE, PFA, FEP) or tubes (e.g. glass, metal, plastic) by means of BOLA Laboratory Screw Joints.

Together with these BOLA Laboratory Screw Joints, the connection is absolutely tight and even suitable for vacuum; the screw joints for GL 14, GL 18 and GL 25 even resist pressures up to max. 10 bar at room temperature.

The system is completed by accessories like quick connectors, dirt traps and GL hose connectors.


BOLA Screw Caps are available as closed caps for closing bottles and vessels with GL thread or as caps with aperture which can for example hold tubes or – in connection with a gasket – be used as septum for sampling. All caps have a handy knurl for easy opening and closing.

They are available for bottle threads GL 14 to GL 45 and are either made of glass-fibre reinforced PTFE, PPS or PBTP. The closed caps are either supplied with an integrated PTFE/silicone gasket or with an integrated PTFE membrane.

The caps which are made of glass-fibre reinforced PTFE have a high chemical resistance and can be used with aggressive products.

PPS offers a high mechanical strength; even caps with small diameters can be closed safely. At the same time, these caps can be used at high temperatures due to a good chemical and thermal resistance.

PBTP caps are an ideal and cheap choice for all applications which do not need high chemical and thermal resistance.



Material                          :              PPS

Temperature resistance  :              from -20°C to +250°C

Chemical resistance       :             + good


Black screw cap made of glass-fibre reinforced PPS, with handy knurl and hexagon. Good chemical resistance, suitable for temperatures from -20°C to + 250°C.

Thread [GL] From tubing O.D. to tubing O.D. [mm]
14 0.8 – 6.0, 6.1 – 8.0
18 0.8 – 10
25 0.8 – 10, 10.1 – 14
32 0.8 – 10, 10 – 16, 18 – 20
45 1.6 – 10, 11 – 16, 17 – 22, 23 – 32