Grundfos 91121957 Counter Flange Kit. CR In-Line Pumps are designed to bring unmatched reliability that can be customized to suit a wide range of industrial and commercial applications. Multi-Stage CR Pumps are versatile, and can be adapted to applications including; water systems, cleaning systems, water treatment, boiler feed, and temperature control. This Grundfos 91121957 Counter Flange Kit is a genuine Grundfos part designed for installation and re-installation of CR Pumps onto the intended system. This Flange Kit comes equipped with two counter flanges, two gaskets, and all the necessary bolts and nuts needed for installation. The Counter Flanges for CR and CRN pumps are made of stainless steel according to AISI 316. This Flange Kit is designed to help mount the pump, keep the pump in place, and provide safe and secure connection.