Trend C208X1/2TC Intumescent cutter set 10mm x 40mm Intumescent Recesser 1/2\" shankFor either frame or door applications, with standard Intumescent Strip. Neatly cuts grooves on doors or frames to accept Intumescent Strip which enables the formation of effective barriers to both fire and smoke. By using alternative ball bearings diameters other seal thicknesses can be introduced. Alternative bearings can be purchased to suit other thicknesses.For 4.0mm thick and 10.0mm width intumescent strip.Specification-D=40 mmC=10 mmB=32 mmE=4 mmShank Diameter=1/2 inch