Abstract: A punch for forming a rectangular opening in cinder block. The punch includes a housing having a wall with a toothed edge and which is generally rectangular in crosssectional shape. A tube is secured to the housing and extends perpendicularly outwardly from the toothed edge so that the axis of tube is positioned within the interior of the area circumscribed by the toothed edge of the housing. A rod having a piercing point at one end is slidably mounted within the tube so that the piercing point is contained within the housing while the other end of the rod protrudes outwardly from the free end of the tube. In use, the housing and piercing point are both positioned against the cinder block. The rod and free end of the tube are then struck by a hammer in order to form the rectangular opening in the cinder block.