Isolation Flange, Bolt Hole Size 0.5 in, Compatible Pipe Size 1/4 in, Compatible with Brand Taco, Compatible with Grainger Part Number 33HM87, 44ZD49, 4JB21, 4JB26, 4PC78, 4PC90, 4PC92, 53VF87, 53VF88, 53VF89, 53VF90, Compatible with Series 0010, 0011, 0012, 0013, 0014, 0015, 0015e3, 0018e, 0026e, 0034e, 0034ePLUS, 005, 006, 007, 007e, 008, 009, 110, 111, 112, 113, 2400-10, 2400-20, 2400-45, VR1816, VR2218, VR3452