Hi Dan, from the Viridian web site, the red laser is good for 25 yds in daylight and 1 mile at night >>> https://viridianweapontech.com/products/lasers-lights/e-series-for-home-defense/viridian-essential-laser-sights-for-rossi-brawler-and-rossi-tuffy ,
Stay safe & have a great day!

Hi Dan and welcome. It is good for 100yds and beyond in indirect sunlight or inside. In sunlight expect 25 or 30yds. A Green laser would be much more visible in daylight. Cheers, stay safe and enjoy!

Where you might “zero” a rifle at 100 yards, you'll probably zero a pistol and laser at a much closer distance, maybe somewhere between 10 and 25 yards. The proper distance to "zero" any pistol is 25 yards for combat; 50 yards if you are shooting bullseye.