A mounting part for an apparatus to be mounted into a cut-out of a countertop includes a rail member having a front wall with a plurality of notches, and a latch member defining an internal cross-sectional space for receiving the rail member in a manner such that the latch member is able to travel along the rail member. The latch member has a front wall with an extension having a terminal end that extends inwardly towards the rail member and which is adapted to be seated in one of the notches, with the latch member being pivotable with respect to the front wall of the rail member. A catch member is pivotably secured to the latch member, the catch member having an end edge for contacting the underside of a countertop. The mounting part also includes a pull member for pulling the latch member and the catch member upwardly.