Snail ID

[Markxc]

Anyone know what kind of snail this is? My ATO float sensor was malfunctioning so i took it apart and found this snail in there. Doesn't look like any snail ive ever bought. Assuming there must be more of these hiding in my tank and wondering if i can keep them.

 

[Gareth elliott]

Looks like a common limpet

 

[Markxc]

thanks