Pratley Pratlok® Grade PEN 4 x 50g bottles.Medium Strength. Ultra low viscosity thread locker for "wicking" into pre assembled fasteners, press fits and knurls. Also suitable for sealing micro porosity in welds and castings. Colour coded lids, indicating strength. Suggested Uses: Use to eliminate loosening of fasteners such as screws, bolts, nuts and studs. Prevent slip or movement between press or slip fitted parts such as shafts, bearings and drives. Pratlok also seals the joint and prevents