The STANLEY SK58 Sinker Drill is a heavy duty rock drill designed for drilling underwater in concrete rock and masonry. The feathering on/off valve makes starting the drill bit easy. The SK58 uses industry standard drill steels and can drill up to a 3Ó (75 mm) diameter hole up to 20Õ (6 m) deep. The direct drive rotation motor drives the 1Ó x 4_Ó hex shank drill steel and is adjustable between 0 and 300 rpm. Air is required to clear holes of debris. Painted high-visibility yellow.