A glass cutter is a hardened steel wheel mounted in a holder. Better quality cutters have replacement wheels. It is used to score a line across a sheet of glass, bending or shocking the glass along the score encourages it to split along the line. Tungsten carbide wheels offer longer life.
A range of replacement Wheels & heads.
Shaws only £3.13
Shaws only £2.40
Shaws only £1.96