The Sony X50011181 EARPAD(R) ASSY(BLACK) is a replacement ear pad assembly for the right channel of a pair of headphones. It is identified as the black version, intended for restoring the ear pad on the matching side.
This is a headphone accessory rather than a complete headset. Its right-side designation distinguishes it from a left ear pad; the listing names X50011182 as a substitute part. The confirmed details identify its side and colour, without specifying material, dimensions or which headphone models it fits.
Use it as the right-channel ear pad assembly when replacing that part. The package contents are not specified in the product information.