I usually use my trusty scholl pedi machine but my feet got really bad after wearing steel cap boots for work and doing long days so I grabbed this to give them a bit of an extra good buffing.
I got mine from life pharmacy and it was pretty cheap around $7. It's nothing fancy but it gets the job done! It can be used on wet or dry feet. I prefer to sit outside as it's a bit messy and slowly chisel away at mine lol.
It does a great job at getting rid of hard, dry skin. I like to slap on some moisturiser and a pair of socks once done and my feet feel super soft the next day. Simple and affordable and does what it should :-)
I always have a pumice stone in the shower since I'm a daily foot scrubber. While this isn't my fave brand and it looks very plain it works. It just scrubs/buffs off the hard skin on my soles and near my heels keeping my calluses manageable. Now the nice thing about this plain one is that the tan colored build up isn't as noticeable as it is on my fave one which has a white pumice stone, which stains pretty quickly. I think if you want something more aggressive then you probably want one that's more coarse, but the Revlon one does a good job.
Tips: I like to scrub my feet at the end of my shower that way my heels have been softening a bit in the hot water and it's easier to buff away at the calluses.