Use for conceal carry?

Well, I’m in CA so concealed carry is a language I don’t understand… lol I’m a gun guy though so I can confidently say, Yes! This belt should be fine for smaller “concealed carry” firearms. It has great, comfortable flex/stretch but still holds sturdy as I do loop lightweight tools with ease. Great belt, I have multiple types but this in particular is my go to for both function and looks. Hope this helps your decision, once you have it you’ll know it’s a no brained!

how wide is the belt?

Haven't measured it but it's a tight fit in the openings in my pants.

Does the buckle set off metal detectors ? Im a security guard at an airport, and have to go through screening many times a day.

It set off the detector at my local sheriff's office door.

does this belt fit with dress pants when you go through the belt loop twice?

This is a wide belt, 1.5 inches. I wear it with my hiking pants which has wide belt loops and I can easily put the part of the belt that over laps through these loops. I can't tell what size loops your dress pants have, so I can't say for sure that it will work for you or not.