This 7-piece set is ideal if you want to prepare plumbing and electrical installations and drill into masonry and stone. It contains 5 carbide-coated core bit inserts in diameters of 33, 53, 68, 73 and 83 mm, a centring drill bit (Ø 8 mm) and a mounting plate. This enables you to drill accurately fitting holes with a cutting depth of 55 mm (e.g. in pumice stone, aerated concrete or similar soft and medium-hard types of stone). The drill bit insert can be quickly locked in the chuck of your drill using the hexagonal shank. The high-quality 2-component plastic box is ideal for safe transport and tidy storage. The core bit inserts are TÜV-tested - so you can rely on safe quality products.