These don't feel much heavier than a standard set of safety glasses to me. Its great being able to just flip down the magnifier rather having to swap out my safety glasses for readers, every ten minutes, or worse, wear a pair of large goggles that barely fit over my readers and fog up too easily. And the price is reasonable enough to buy extra pairs, for when you lose the magnifying attachment, which while reasonably well made, will still catch things and pull off easily, especially when flipped up. I was a bit confused by the 1.5 power/2.5 diopter lingo. I vaguely understand the difference between magnification and diopter. It seems to mostly affect the range of magnification, in that the degree of magnification varies between the two distinctions the farther you are away from what you're looking at: 1.5 mag will be clearer at 5-8 feet than 1.5 diopter, but they'll be about the same clarity at 1-2 feet away. For 5-8 feet distances, 1.0 diopter would be more equivalent to 1.5 mag. These glasses however, have almost the exact same magnification properties of my 2.5 mag readers in terms of reading clarity up close. So, I'm at a loss as to why they claim only 1.5 power. Regardless, they currently suit my needs well in that department. Any work beyond arms length becomes blurred. But you just flip them up and keep going. These are not bifocal magnifiers. The entire flip down lens magnifies, which is what makes them so ideal compared to other alternatives for those who just need something for up close, not for a distance yet. I haven't used these in the summer yet, but based on just a few warmer winter days here in the humid south, I suspect a head strap will be crucial in warm weather, if you're not working in the AC. The nose piece doesn't feature any rubber coating to keep them from slipping down your nose when you start to sweat. That might be just as well, as flexible rubber pieces tend to fall off, and fixed ones tend to dissolve from the salt in your sweat after a season. Unfortunately, snugging them against your face will cause them to cloud a bit, even if you're not noticeably perspiring. A foam or rubber top that keeps the lenses farther away from your brow would probably go a long way toward alleviating this. Though, ideally, I'd also love to see these offered with a foam liner that fits against your face, fully encircling each lens. I fell in love with such when riding motorcycles, as in addition to not fogging up nearly as easily from sweat, it keeps the air out of your eyes, something that would be extremely helpful in fields where wearing a dust mask along with goggles is routine.