Ultra-dot,..have shot a couple thousand rounds through my Casull and she still works great,...I dropped it twenty ft. out of my deer stand one year,the only thing that happened was it knocked my zero off-about 8 inches to the left,...I zero'd her back in and she's been doing great ,...the incident was a couple of years ago,...but this red dot is I think at least twelve years old,maybe 13.I also have an ultra-dot on my Encore .500 S & W magnum and shes doing great.