This is the black plastic piece that goes around the shifter slot and slides up and down when you put in gear. A very often worn, damaged or missing part. Made of flexible plastic and has textured grain on one side and smooth on other side. Measures 13" long x 1 1/2 inch wide. 

Fits: 1964-1967 Chevy Chevelle Super Sport and Malibu Super Sport with Automatic Console.