R25 35mm Threaded Button Bit for Rock Drilling The R25 35mm dome threaded button bit is a top hammer rock drilling tool engineered for underground drifting, tunnelling and small-hole bench drilling operations. Featuring a normal skirt body and 7 durable spherical tungsten carbide buttons, this rock bit offers high impact toughness, smooth energy transfer and a long service life in medium to hard rock formations. Product Overview Equipped with 5 gauge buttons (7mm) and 2 front