The UTG AR15 Ambidextrous 45/90 Safety Selector is not compatible with the M&P15-22. Unfortunately, we do not currently carry any M&P15-22 specific fire selectors.
Yes, this should work on mil-spec .308 lowers.
I'm not sure... let me look at the description...
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Product Info for Leapers UTG AR15 Ambidextrous 45/90 Safety Selector
UTG AR15 Ambidextrous Safety Selector, Aluminum and Steel Construction, Reversible Short and Long Oversized Levers Finished in a Matte Black Anodization, Configurable for a 45 or 90 Degree Throw, Includes Installation Tool and Hardware, Detent, and Detent Spring
No, this only a 2-position safety selector.