This is a AmeriGlo Sight known as the Pro i-Dot, model SW-245.
Utilizing a dot-over-dot configuration" their i-Dot sets have an extended square-notch rear for increased sight radius with a glare-reducing undercut rear face. The i-Dot sights provide a quick and easy vertical sight alignment" making it an excellent choice for all shooters.
Features:
Green tritium .140 wide orange outline front
Green tritium .165 wide round notch rear
Fits M&P Shield
