The study describes the examination of the mechanical properties of potential materials for printing on a 3D printer and the selection of the optimal one for the production of the power supply connecting element for handheld tools. The test methods used for the purposes of this work are the tensile strength test, the Vickers hardness test and the impact fracture test. ABS, PET-G and PLA materials were tested. According to the test results, the material PET-G was selected for the production of the power supply connecting element for handheld tools. The goal of making a power supply connector for handheld tools is that products whose parts can be changed after their lifetime are slowly being removed from the market, but also because the tool parts of certain manufacturers are more affordable to consumers than some other manufacturers. For the aforementioned reasons, there is a need to produce various connecting elements, that is, affordable adapters. The process of making a connecting element through 3D printing is complex, and very precise measurements need to be made so that, after printing the parts of the model, they are compatible with the handheld tool for which it is made. Such a model requires the implementation of testing and optimization for the purpose of functionality, durability and cost reduction (the amount of materials used and the design of the final product). The parts of the model of the connecting element were joined into a whole and the functionality of the connecting element was tested and described.