Aim without thinking, the Lasersaddle red and green laser sights are available for Mossberg® 500, 590 and Shockwave 12 gauge shotguns. Click HERE to learn more. See link below ad to purchase on Amazon.
Crimson Trace LS-250G Mossberg Shockwave Laser Saddle
Green Laser Sight for Mossberg 500 & 590 Shotguns
Source:: Selling the Second Amendment