What's this tool called?

[blackravencross]

I keep seeing this tool when I scroll through Instagram and I really think I would like to start investing in the time to start doing my own nails. I get them done in the salon regularly but often times I feel like what I want to do I can probably start achieving on my own but I want to use this tool and I don't know the name of it to look up where to find one, cost, etc. It almost looks like a doorknob. Link below for an example of the tool: 

[SportyGirly125]

@blackravencross your linked got removed because you can’t post outside links here. Is this what you are talking about? I got mine from Amazon years ago. They have different kinds but I just took a pic of the first one I found.

[blackravencross]

My bad I'm still learning! So after multiple attempts at trying to figure out how to attach a screenshot (file size too big), I ended up going to a nail supply store and asking them. It's a practice nail tool, and I found some on Walmart.com and some on Etsy, both are magnetic and exactly what I was looking for. Thank you for your time though!!