Rohl QN25UM Undermount Sink Kit, 25 Inch Vance. The QN25UM is a genuine product manufactured by Rohl. This particular product is an Undermount Sink Kit which has a 25 inch Vance. This installation kit is for use with Rohl Allia sink models; 6307 5927 6347 6337 6339 6737. It is important to note that in order to correctly mount the 6737 Allia sink, two units (sink kit) of the QN25UM. One year on manufacturer defects.