Kit comprising three spray products that allow the detection of defects in welds or castings such as cracks caused by strain, pitting, porous areas and cracks in welds. These areas can be identified with ease and precision. For the detection of cracks, fusion defects and open cavities in welded parts. This non-destructive testing method allows efficient checks to be conducted on the quality, conformity and uniformity of surfaces. How to use: 1) Thoroughly clean and degrease the surface to be treated with the cleaner (blue). 2) Apply the penetrating liquid (red) evenly. 3) Wait 20 minutes for the product to penetrate all defects and dry. 4) Remove excess penetrating liquid using the right solvent and then dry. 5) Spray a thin layer of Crack detector (white) over the area and leave it to work. 6) Following reaction with the penetrating liquid in the cracks, the Crack Detector informs the user clearly and unequivocally of any defects in the surface for quick corrections.