Ultrasonic welding in medical technology is spreading faster and faster. Mostly small, but very complex shaped devices, wearable „smart” devices, drug delivery systems, surgical devices with small wounds, catheters, etc. Below we present one of these, a body-worn device to reduce the risk of thromboembolism, branded „geko branded ”geko". But we also show how these welding machines are constructed, how they how they are built, how to handle them, what faults to expect and how to get them repaired.