I tried it on as a test. I bought it for overseas travel, but I ended up not using it. The WP21 is a tough smartphone, so I'm not sure if anyone needs a cover, but I'll put it up for sale. Those who have a WP21 will understand, it will increase the thickness even more. I'll specify that it's for people who want to try it out. It probably won't fit other models at all. The camera hole is right on the edge, so I think you should avoid similar models too. It didn't interfere with the WP21's camera.