This was exactly what I needed! I work as a hygienist and use loupes daily. I had been using the original cords that came with my Q-optic loupes and they would constantly slide off in between patients. These new holders have stayed put ever since I placed them on! It’s been about 3 weeks and I haven’t needed to adjust them or anything:)
I love this product. Very well made, will outlast your sunglasses. It's my favorite of all the various brands I've tried over the years. The thin strap makes it low profile, but very sturdy. It's adjustable to tighten up when needed to keep your sunglasses on your face, but I usually wear it expanded to its maximum length so I can wear my sunglasses around my neck and not have to hold them or put them away when temporarily taking my sunglasses off.