These cleats are used in place of the standard SPD cleats, and allow you to twist your foot out of the pedal in any direction, including a hard yank straight up. This means, when your bike is going down you can literally leap out of the pedals and land on your feet rather than being pulled over with the bike. For many mountain bikers it is a good compromise between clip-in pedals and flat pedals, and is also great for road or cyclocross. These have several times saved me from more serious injuries.
I have SPD pedals on all of my bikes, including the road bikes. I only use mountain bike shoes because unlike road shoes you can walk in them. When I bought a new pair of shoes I needed new cleats. I saw these on sale and gave them a try. They are way easier to release than the standard SPD cleats while still secure when clipped in. So much so that I am now thinking about putting them on all my shoes.
These have multiple points for disengagement, so they're really easy to uncleat in an emergency situation. They'll sometimes pop out in the upstroke when you're really cranking it, but I like them for casual and urban riding when you have to clip in and out a lot. Also highly recommend for those new to cleats, both off or on on-road, and for commuters. I've never had any de-cleating accidents with hem, knock on wood.
In the interest of being helpful, I'll provide candid feedback on these cleats.
To be honest, didn't like these at all, because was used to the black ones that were more secure. I was popping out of them right and left, even after tightening them. I ended up taking them off and buying a pair of the black ones to replace them.
Hope that's helpful. Sorry it's not more positive feedback.
These are by far my favorite cleats for any bike that I have SPD pedals on. The multiple angle release makes them much easier to unclip from the pedals then the standard cleats. This makes these much safer to use that I highly recommend them for beginners that are converting to clipless pedals. I have never had a failure to release in any situation which required my to do it quickly. This includes mountain bike riding where getting out of the pedals in a hurry is really important.