The Rolleiflex Automat MX-EVS Model K4B is a medium-format twin-lens reflex camera shooting 6×6cm frames on 120 roll film, produced by Rollei in Germany during the 1950s. It sat in the company's professional TLR line, with the MX-EVS designation referring to the built-in flash sync and exposure value coupling between shutter speed and aperture rings.

Auction data for this specific K4B variant is thin: a single UK saleroom result from March 2023 saw one sell for £262 at hammer. On that limited evidence, clean working examples in 2026 appear to trade in the low-to-mid hundreds at auction-hammer level, though condition of the taking lens, shutter, and focusing screen heavily influences what any individual camera is worth.