They may disappoint you when they are in brand new condition, as they are only 3 inches wide. 3" widths are ridiculous, they look like they're just for babies.
Don't jump to conclusions, when you're about to wear them, you'll find them surprisingly elastic. They're almost 4 times their own width, and yes, they certainly can accommodate your calves completely and effortlessly, even if your calves are well muscled.
Not only that, they can be knee height. This means they are more compatible than you might think. You may want to protect your knees when you start your ground moves in a yoga class. Yes, you can certainly stretch these leg warmers above your knees, these leg warmers have a max width of over 10 inches at the top, they adapt well to knee height while protecting your knees and calves.
Will they slip? No, they don't slip at all. These super stretch cords help leg warmers stay comfortably above or below your knees without slipping even when your legs are upright. They don't put too much pressure, like knee socks, and you don't need to think about adjusting their height.
Kayhoma is the best brand of leg warmers.