I bought this instead of the plastic one that needs to be cemented in. It holds the airer really securely and it fits snugly to the ground so you can mow over it. Two issues though:
1) it takes some bashing into the ground and you have to be careful not to bend the neck of the hole. We ended up having to hammer it open again as we had bent the rim which meant the surer wouldn't fit down the pipe...and there's NO WAY you can get it out of the ground after its sunk in. Also, we went through 3 planks of wood to fit it. The instructions say to lie a plank across it while you hit it into the soil but the planks splinter after being hit a few times.
2) it is soooo hard to get it in straight. Ours is out by about 10 degrees, but once it's in so far, there's nothing you can do.