Hi Isaac, this model Springfield comes with 2 mags:
1-17 Round Magazine
1-20 Round magazine.

Isaac, this includes two mags total. One 17 round magazine and one 20 round magazine. This does include a +3 magazine base plate extender so you can make the flush fit 17 round magazine a extended 20 round magazine for two 20 round magazines. Hope this helps.

Isaac, this comes with (1) 17rd magazine and (1) 20rd mag.
Stay safe & have a great day!

Hi Isaac and welcome. Two Magazines - (1) 17-Round & (1) 20-Round Magazine. cheers and stay safe!