This key passes into the keyways for all of the GM 6-cut keyways, including B44, B45, B46, B47, B48, B49, B50, B51, and B52. It is a handy key to keep in stock in case you run out of any of those others, but keep in mind that the key is thinner (breaks easier) and is also stamped with the words "For Locksmith Use Only". If you hand it to a customer, make sure they know it's for temporary use only until you are able to replace it with the real key.