HMCT - Hard Metal Carbide Tipped Drill Bits. The hard metal used in this model is Tungsten Carbide TCT Contains 5 Bits: 4mm, 5mm, 6mm, 8mm, 10mm For Masonry, Brick, Block, Concrete, Stone etc Can be found on Makita UK website https://makitauk.com/product/d-72877
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