In compliance with GOST 10994-74, the alloy grade (except thermostatic bimetals) includes a two-digit number that designates the average weight percent of the element and the letter of the element after the number. Iron is not stated in the alloy grade. In the thermostatic bimetal grade the weight percent is stated after the element number (so as for ordinary steel). Letter “A” at the end of the grade means strict requirements towards metal purity. Letter “E” means that the alloy is hard-magnetic.