Zero Clearance Liner For Bib18Pb, Bib18Ir & Bib18Rt This 18-Inch Zero Clearance Liner Is Specifically Designed For Use In Custom Outdoor Kitchens. Designed To Fit The Bib18Ir Dual Infrared Drop-In And Bib18Rt Dual Range Burners This Zero Clearance Liner Allows Combustible Building Materials To Be Installed Near Or Against The Liner Without Fear Of Combustion Or Heat Damage. This Makes For Greater Flexibility When Installing Drop-In Burners In An Outdoor Kitchen Application. Please Consult Your Manual For Installation Instructions.