Trend C220X1/4TC Intumescent Cutter Set 15mm x 24mm Intumescent Recesser 1/4\" Shank FEATURES 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 15.0mm width intumescent strip SPECIFICATION D: 24 mm C: 15 mm B: 16 mm E: 4 mm Shank Diameter: 1/4 \" Fire check: 45 minutes