I didn't see an added length measurement on that Strike Industries. How much longer would you say it is?
I use the Strike Industry's extensions. They work great.I prefer the Strike Industries +2 extension on the 7 round magazine. They are about half the price of many others two. For Strike M&P Magazine SHIELD +2-Round EMP Industries 9mm/40 S&W Plus Extension | eBay
Here is another one that looks identical but even less expensive. Solid Enhanced Magazine Extension Plate 2 Rounds For 40 S&W M&P-SHIELD 9mm | eBay