laying

I have been fixing slabs that were not level. Is there a tool I can buy for tamping them down better? I seem to remember one but forget whats its called LOL.

Hi, Hopefully I'll be at the point where I've fixed my bedroom floors and can lay the gripper rods soon.. Issue is all three bedrooms have old hearths - apparently you still need gripper rods on top. Two of the hearths have beautiful original tiles, I don't intend to do anything with them...