Manual valve seat cutter, made by Yon Fong, best in the world. Works very well, but requires good setup. Cutters are carbide and extremely sharp, comes with 7 cutters all new. 15 pilots, and everything else you need. The magnet works very well, it is 110v. The unit is very accurate, and will work with all cylinder heads, you just need the right pilots. This is a great low cost starter unit.