Meritor with 16-1/2" "Q" & "Q" Plus Brakes,MUST REPLACE RIGHT & LEFT HAND S-CAMS WHEN "Q" PLUS CAMS ARE USED TO REPLACE EARLY DESIGN S-CAMS., "Q" PLUS S-CAMS MAY BE USED IN "Q" APPLICATIONS; "Q" S-CAMS CAN NOT BE USED IN "Q" PLUS APPLICATIONS., Left Hand Shown