Miniature wonderland: This is what an electric air pump looks like on the inside

Viewed from the outside

From the outside, the Nano Fumpa Pump looks like a minimalist gadget, barely bigger than a lighter. But inside is a fully-fledged high-pressure compressor that supplies enough air to bring a 700×30c tyre back up to 4 bar in around 60 seconds. A small power station for your jersey pocket.

The performance

The centrepiece is a cylinder with a diameter of 15 mm and a stroke of 15 mm. Each piston stroke produces around 2.6 cm³ of air volume. A 30 mm tyre holds around 1.5 litres of internal volume - around 7-8 litres of "free air" are required for 4 bar. This corresponds to around 2,800 piston strokes. Theoretically, just under 3,000 rpm would be sufficient, but due to losses and increasing back pressure, the engine actually operates in the 6,000 to 10,000 rpm range, which is why it makes so much noise!

The energy

The energy is supplied by a 7.4-volt battery with 300 mAh, which is quickly recharged via USB-C. Despite the low capacity, the power is sufficient for three to four emergency fillings, as the motor only runs for a short time, but extremely efficiently. The compact design explains why the pump weighs hardly more than a bar.

Against heat exhaustion

A small circuit board takes care of all the controls: it regulates the motor power, temperature switch-off and automatic stop before the system overheats. Displays or sensors are deliberately absent - the pump favours simplicity and robustness.

For travelling

Together, this results in a tool that you hardly feel until you need it. One press of the start button and the tyre inflates without any effort. A miniature miracle that shows how much technology fits into 96 grams of aluminium and costs 80.95 euros.