Built to still be on at bedtime.
A soft silicone band at the top holds the sleeve through stairs, shifts and long walks. No hitching it up every ten minutes.
A fine breathable knit that doesn't turn into a sweatbox by noon. That's why it's still on your leg at two in the afternoon.
A measuring card comes in the box: four inches above the kneecap, straight to a real size chart.
Slim enough for jeans, work trousers or scrubs. Machine washable at the end of the day.