Part number 33521114974 is a Genuine BMW Protection Tube (also referred to as a protective tube or rear shock absorber cover). It is a critical component of the rear suspension assembly designed to shield the shock absorber shaft from dirt, road debris, and moisture. I have 1 pair left in stock and the "price each" is based on buying both parts. (27c)
This part is primary to vintage and classic BMW platforms, most notably the BMW 3-Series E21 generation (1977–1983), fitting models such as the 320i, 316, 318, and 323i. According to dealership parts catalogs, it also services specific vintage variants or acts as a supersession line for select older trims of the E12, E23, or Z3 platforms depending on the exact suspension package.