The M4 nut union system, made of durable plastic, is a small piece with a grooved design on the outside which allows it to hold the boards with greater precision and grip, it also has a transparent finish and a hollow cylindrical shape. Its installation is through a drill that is made in the surface of the furniture, therefore, the part of the nut union system is completely embedded in it. The function is to serve as a support for M4 screws that require a suitable surface for mounting. The packaging of these nuts contains 2,000 units.