The classic among thermometers

The glass thermometers have a far-reaching tradition and analog thermometers have long been the method of choice for measuring body temperature. However, glass thermometers still offer some decisive advantages today. Due to the closed glass body, the thermometer can be disinfected as a whole and is ideal for allergy sufferers. And our thermometers have long since stopped containing toxic mercury. Today Galinstan is used as the measuring liquid.

We believe in a tradition that goes back more than 100 years and are convinced that it is still an environmentally friendly, reliable and, above all, durable variant of digital thermometers.

Important Documents


We produce our thermometer exclusively (95%) with raw materials from Germany. Properly stored, it accompanies you for a lifetime.

Suitable for allergy sufferers

This thermometer is particularly suitable for allergy sufferers. The closed glass body is free of metals or plastics. It can also be cleaned and disinfected 100% safely.

Special glass from Germany

We only use special glass from Germany to manufacture our thermometer. The glass tube and the internal capillary are manufactured in-house.

Without batteries

The measuring principle of the thermometer is based on the thermal expansion of materials, which is why this thermometer does not need batteries. The non-toxic measuring liquid Galinstan replaces the previously known mercury.

Every thermometer is unique.

Our thermometer is real manual work and each of the 25 work steps is subject to strict quality control. Each thermometer is calibrated, which guarantees measurement accuracy. That is why there is a small line mark on every thermometer, after which the scale is fitted. This has an impact on how the scale looks, whether more or less white space or 35 °C is specified or not.

The different scales and the line mark are not a quality defect, but are due to the manual production and the uniqueness of each thermometer.

Reset measuring liquid

The measuring liquid must be reset before each new measurement. You can do this in no time with the included "easy flip" shaking aid. Place the thermometer in the device and grasp the upper end of the shaking aid between your thumb and forefinger. Now all you have to do is make the easy flip vibrate.


Measure and evaluate temperature correctly

Not only the right measurement time, but also the choice of a suitable measurement location are crucial for accurate measurement results.

A thermometer for all ages

The Geratherm® classic thermometer is intended for determining the body temperature of people of all ages. It is suitable for rectal, oral and axillary measurement. We recommend rectal or oral measurement. For children, the measurement should be performed and supervised by an adult.


Rely on sustainability

With the purchase of a glass thermometer, you are choosing a durable product with consistent measuring accuracy. Always keep your thermometer safe in a protective case and you will enjoy it for a very long time. The thermometer is delivered in a protective cover as standard. The classic+ variant contains a storage case with an integrated magnifying glass function and shaking aid.

Geratherm® classic+ - The storage case with integrated enlargement function

With the special storage case, the measurement results of the thermometer can be read even better. After the measurement, insert the thermometer into the slot and slide it into the case. The magnifying glass function helps you to read.

Technical Data

Measuring range 35,5 °C to 42,0 °C
Measurement accuracy +0,1 °C / - 0,15 °C
Intended purpose Medical glass thermometer for determining body temperature
Measuring locations rectal, oral, axillar
Storage conditions -15 °C to 42 °C
Please refer to the instructions for use for full technical data.

Questions and answers

You have to reset the measuring liquid of the thermometer before each measurement, in our case it means shaking the thermometer.

Hold the thermometer between your thumb and forefinger. The tip of the thermometer points towards the ground. Make sure that no objects such as a table, chair, etc. in your immediate environment that could break the thermometer. Now start shaking your wrist with quick movements. The measuring liquid sinks.

Note: Contrary to the hard hitting of the thermometer known in the past, you now need speed. Today's Galinstan has different material properties than the mercury of the past.

To make it easier for you to lower the measuring liquid, we have developed a shaking aid called "easy flip" for the Geratherm classic. Push the thermometer into this and hold it at the upper end. Then start shaking it. The plastic begins to vibrate and amplifies the natural movement, resulting in faster fluid reset.

This is the only way to reset the measuring liquid. Fridge, cold water & co are useless.


The silver line you see at 38°C is a calibration mark. This indicates that there is a temperature of 38 °C at this exact position of the measuring liquid. This marking is required for the production process and ensures the measuring accuracy of the thermometer.

No. The little bubble is a deliberate narrowing of the capillary tube which prevents the column of liquid accidentally flowing back into the container (maximum principle).

From the point of view of safety, the temperature should be measured rectally with a clinical glass thermometer in children, especially babies and young children. With oral measurement, you cannot be sure how hard the child might bite the thermometer. This could break the thermometer. The axillary measurement is also not recommended because a child cannot yet be expected to place the arm correctly and press it towards the upper body. The lack of physical contact can lead to a false measurement result.

In principle, rectal measurement is preferable for babies and small children, since an exact result can be guaranteed here. To do this, insert the tip of the thermometer with a maximum of 2 centimeters into the anus. To make insertion easier, you can put some baby oil on the tip.

If your child has persistent fever or if you have further questions about temperature measurement of children, consult your pediatrician.

Note: When taking a child's temperature, stay focused throughout the measurement

You can reuse the Geratherm® classic glass thermometer as often as you like. Clean your thermometer before each use.

Important! If the thermometer is cracked or already broken, stop using it. Dispose of this in the household waste.

The Geratherm® classic should be cleaned after and before each measurement. Since it is a closed glass body, you can wash it with soap and water and then dry it. The water must never be hotter than 42 °C. You can also easily disinfect the thermometer. Immersion disinfection is also possible.

Carefully pick up larger pieces with a dustpan and brush. Ideally, the liquid should be vacuumed up. The tin in the liquid can leave grey-black marks if it is rubbed in. These can be removed with standard household floor cleaning products.