Quality construction, but why no button assist? - Smith & Wesson Magazine M&P15-22 22LR 10 Round (PKGD)

This is essentially identical to the standard 25-round magazine, with two differences: There is a small metal roll pin inside limiting capacity to 10 rounds, and there is no sliding button assist. These are available from aftermarket vendors, but require some modding, as the pin prevents the follower from being positioned to install the button. To install an aftermarket button slider, the roll pin can be removed with a few heavy sledgehammer hits with a screwdriver, but doing this will of course convert the magazine into a 25-round capacity magazine.

If you live in a state with a 10 round limit, this could be a problem. And if you live in a free state, you probably just want to buy the 25 round magazine instead.