Product diversity


Questions and answers

FAQ - Frequently Asked Questions - in this section you‘ll find our answers on many of your questions already. We keep this page permanently updated.


I cannot find a suitable contact in the Fixtest catalogue or here on the web? What should I do?

Can I order series xy with head style 123?

Please contact us, we can do many things.
First, it is possible that our records are not quite up to date - although we always try our best. Many head styles are available in certain series as s standard, because a customer wanted it like that. So it is quite possible that the desired head shape is already available. On the other hand, there is often a possibility that we combine parts from different series types - and finally we can simply take the new part in our production.

What's XXLonglife?

XXLonglife is our answer to the problems caused by lead-free soldering. Due to the repellent surface tin deposits or other contaminations have no chance to adhere to the probes. The contact quality is improved and the life cycle time of the probes are extended. XXLonglife reduces material wear, and annoying pseudo errors in the test-line can be avoided which reduces costly maintenance work -> less is more!

Technically speaking XXLonglife is a nano coating that we apply in addition to the gold surface. This layer has a thickness of about 2-3 nm (nano-meters). The surface becomes dirt repellent (hydrophobic), at the same time very hard and smooth (reduced friction). For example, the insertion and extraction forces of a connector with XXLonglife are reduced by about 50%.

Further information about XXLonglife

What is a metric spring probe?

In the production of printed circuit boards (pcb), the american inch unit has become standard for the declaration of the pitches between the centres of conducting pathes. The pitches are specified in mil (1 mil = 0.001 inches = 0,0254 mm). Commonly used are pitches of 50, 75 and 100 mil.

Metric spring probes follow the metric system and so the holes for the receptacle can be drilled with in europe common drills.

Besides the differences in the dimensions, metric spring probes and receptacles have collars, which are used as stops in the fixturing of receptacles and test probes. Additional spacer tubes can be installed between the collars of receptacle and probe to easily achieve variable extension heights.

How does the color verification with the FINN sensors work?

The FINN, Smart FINN and Ultra FINN sensor verify the color of your built-in LEDs. Additionally they determine also the brightness. Especially the Smart and Ultra FINNs are true allrounders. They not only verify but recognize the colors of your LEDs - one sensor for all colors. The measurement of the color and brightness are output in the same signal.

Find more information on our FINN product page.

Product information

Are spring loaded contacts waterproof?

Yes, that's possible. In general, spring loaded contacts are not waterproof. Waterproofness isn't a major feature in the testing business.

But when it comes to charging portable devices designed for outdoor use like sports trackers or remote controls of construction machines, it's getting more interesting.

It only needs little changes to our standard contact design to fulfill a IPX7 rating for a battery contact

Does temperature have an effect on the current carrying capacity?

Temperature, current carrying capacity and electrical resistance of a contact all have an effect on each other.

Current flowing thru the pin heats up the pin, depending on current load and design type. With rising temperature also comes increased resistance, which will cause a decrease in the contacts current carrying capacity. Should the current load or temperature raise further, e.g. by lacking enough ventilation or cooling, the electrical resistance will also increase causing an again rising temperature. This process can repeat itself until the probe finally burns off.

Our specifications on temperature and current load rating of our contacts always leave some space before they finally reach their real limits, but the described dependencies of physical quantities have to be considered when using spring loaded probes or in the design process of a test fixture or a connecting solution.

If you need any help regarding these topics, we will be glad to support you in finding the right solution.

What determines the current carrying capacity of a pin?

Long story short: The surface plating of plunger and barrel, plus the quality of the contact between these two components.

Current always follows the path with the lowest resistance. In a spring loaded pin, therefore the contact between plunger and barrel should be as good and stable as possible, because otherwise the current mainly flows over the less robust spring.
To ensure a good contact between plunger and barrel, there are several special high current plunger types, designed to increase the force which presses the plunger to the wall of the barrel.

Of course the cross-section of a small barrel is not really much - just a thin-walled tube. For very high current loads a pass-thru plunger is unbeatable.

What defines the max. temperature the pin can be used at?

The critical part here is clearly the spring. Depending on its material it allows certain maximum temperatures.

Springs made of normal music wire are rated up to 120 °C. Is stainless steel the material of choice, temperatures of 220 °C to 250 °C are possible.

But be careful! Continuous exposure to high temperatures over longer times (several days) can lead to diffusion of plated surfaces or corrosion of the base materials.
For these applications, we developed successful special solutions for our customers.

Do you provide 3D/CAD models of FIXTEST products?

Yes, we do! We will send you 3D models on request. Please send us a request and tell us which filetypes are best for you.


How to drill the holes for the test probe receptacles?

For our standard test probe series, we provide a drill size table and a drill parameter table. You will find both documents on our download page.

If you need further recommendation or information on installing our spring contact probes, we'll be happy to help you.

Caig contact cleaners

Is the CAIG product line of contact enhancers specifically made for test probes?

No - CAIG contact care products are not designed specifically for test probes, but are widely used in the maintenance of electronic connectors, switches etc.

Typical markets are audio / video / hifi / aerospace and many other applications. The major job is cleaning and enhancing of connectors, switches and control elements for optimum signal transfer.

In the application of surface plated contacts in the test business we find the same conditions: coated surfaces and the highest possible signal transmission quality. Also contamination loads are often an issue, so an effective and reliable protection of the contact surface is essential.

We have some recommendations for cleaning and maintaining spring contact probes and test fixtures, especially with CAIG products: Infoblatt Pflege und Wartung von Federkontaktstiften und Prüfadaptern (german, PDF)

How do I maintain my faders and slide pots?

CAIG's DeoxIt Fader is the perfect solution for the maintenance of faders and slide pots. It is especially designed for conductive plastics and carbon-based controls. DeoxIt Fader lubricates moving parts and enhances the signal quality.

DeoxIt Fader is the only product authorized by Rane for the maintenance of their potentiometers.

Maintenance procedure recommended by Rane for their faders (link to


I'm from country XY. Can I order directly from FIXTEST?

Please take a look at our list of our international distributors.

If there is a distributor for your country/region, please contact him. Otherwise you can send us your request.


What does the cactus in your company logo mean?

The main feature of a cactus is its needles; and so it is for FIXTEST: We impress with the excellent quality of our needles.