There are some explanation for it,NdFeB magnet's trademark is classified by NdFeB permanet magnet marterial 's(BH)max.N35's average BH is 35MGOe,and N38 is 38MGOe.and so forth.differents of type NdFeB magnet have different production mothed.we have supplied more productions knowledge about NdFeB magnet.you can visit our website.