ID help

[scotts8826]

I've noticed 3-4 of these things on my glass. One thing I've already learned in this hobby is that good things typically do not just pop up in my tank. I've already smashed a couple of them but then decided I should ID them. Any help out there?

 

[ISpeakForTheSeas]

Looks like either a chiton or a limpet - I honestly can't tell which from the pic, but both are good CUC.

 

[scotts8826]

Thanks for your reply. I'll stop my purge and see how they develop.

 

[kevgib67]

Looks like a limpet, I bought some from Reef Cleaners for my tank.