You are looking at the back seat with fold down armrest from a 66 Pontiac Grand Prix coupe. The color is blue. While the seat style is most likely unique to 65 66 Full size Pontiac, it should fit other 65 to 66 GM full size 2 door hard top including Chevy Impala, Pontiac Catalina & Bonneville, Buick Wildcat, Olds 88 etc. The seat back is 54 inches wide. The base is 56 inches wide. The covers are not torn but are brittle. Speaker cover has light pitting. There is one rusted bar on the base frame (pictured). Otherwise, the padding, frame and springs are solid. Usable driver quality as is or great core for re-upholstering. Would look good in your 55 to 57 Chevy.