CEN grade stands for Central European Norm, which is a testing standard for padlocks. Padlocks must pass through a number of intensive tests in order to achieve a certain CEN grade. There are 5 levels of CEN grade, ranging from 1 to 6. CEN grade 6 padlocks are the highest quality padlocks, offering maximum security. At Locks Direct, we offer a range of CEN grade 3 padlocks, CEN grade 4 padlocks and CEN grade 5 padlocks for best protection. Check out our high security padlocks here.