Lens Hood
like PENTAX PH-RBB

One of the most important accessories for each lens you own. A lens hood provides multiple functions: it shades the lens from stray light, improving your contrast and image quality, in inclement weather, it can assist in keeping moisture or wind-blown debris off the lens, and it protects the front barrel from the inevitable impacts against walls, door frames, and other real-life obstacles.

Fits to PENTAX smc DA 50-200mm F4-5.6