I got these shin guards because I was always garfing up my shins, sometimes even while wearing long socks. Now I never lift unless I have these on, whenever I can help it (deadlift, clean, snatch). They've been quite effective.
They're thin and light. Some sort of flexible but durable plastic on the inside, sandwiched inside thin outside layers. Velcro closures at the top and bottom.
If I had to make one complaint, it's that there's no ventilation wherever they cover you, once they're on (the backs of your calves will be mostly uncovered). To be expected, considering the design. So without socks, you might get a bit sweaty; with socks, they might feel somewhat on the warm side. It's a tradeoff I'm willing to make to save my shins, but I can see some folks not being quite on board with that.
In case anyone's curious: the material isn't wearing thin at all at the usual bar contact points. I've had them for about a year now.