The SMC Pentax 500mm f4.5 is a big, heavy lens: it weighs almost 3.5kg and measures nearly 44cm long. It is not the sort of lens that you pack in your bag just in case. But it has a handy built-in tripod mount, a "gunsight" for general aiming, and image quality is solid. Fun fact: this lens technically has an interchangeable mount, which can be switched between M42 and K mounts; only the K mount is included here. Cosmetic condition is excellent, with only very minor wear. Optics are very clean, with only very small marks which will not affect imaging. A neat lens in solid shape.