During the year, JSC "HELP Composite" together with LLC " TD "INTEK" carried out the development and testing of metal collet for prestressing concrete structures. Collets used in the application on metal break off the composite inside. Collets with polymer inserts are short-lived. Therefore, we were faced with the task of developing and implementing metal collets that are durable and reliable, introducing prestressing of the composite into the technological cycle of concrete products factories, as well as making a structure with prestressed composite reinforcement, testing it and analyzing the work of the composite. The end of this work was the production and testing of the PC 72-12-8 floor slab with a load of 800 kg/m2. The video of the process can be seen at the link https://youtu.be/DSrysoAukUk The collet showed itself from the best side. The prestress of the composite was 750 MPa. The use of such collet is technologically safe and does not differ from the cycle of work with metal fittings. The floor slab with prestressed reinforcement withstood the tests in accordance with n. The maximum load was 12 tons (1.4 tons per m / sq). At the same time, when removing the weight, the plate returns to its original rectilinear state. The destruction of the plate occurred after reloading it with a weight of 10.5 tons. Tests have shown that the use of composite reinforcement in critical structures is effective and safe. It should be particularly noted about the properties of structures after removing the load to return to their original state without damage. It is worth thinking about the use of composites in earthquake-prone areas, because this will lead to a significant reduction in damage.