USP magazines

[EmptyMag]

I thought this had been discussed here before but I found nothing doing a search (other than magazine spring part no.'s)
I am looking for 12 rd magazines for my USP Elite and Expert, both are .45 ACP.
In the Operator's manual, it calls them out as HK Part No. 217710.
I have found some that have HK part no. 215957 - for the USP in .45 ACP w/Ext. floorplate?
Can anyone tell me what handgun uses the 215957 and will they fit and function in an HK USP Elite and Expert.
If it truly fits the USP, what is the difference between the 215957 and the 217710?

Thanks in advance.

[Kochaholic]

Yes, the magazines are identical. The only difference I can see is whenever that mag was referred to as 215957 it came with an extra floorplate.

[EmptyMag]

Good.
Thank you.