Required on 4-door Tahoe/Suburban/Yukon models when installing a Rough Country 4in or 6in kit.Only fits 4-door models1-2 houshttps://s3.amazonaws.com/roughcountry/install/1038.pdf1992-1994:4WD:Chevy:K1500 Blazer;1995-1999:4WD:Chevy:Tahoe;1994-1999:4WD:GMC:Yukon