Whilst the the AC5000 is the little brother of the AC600 chrono, are there differences between these two products from Acetech? BB2K Airsoft reviews this for you to find out... "The AC5000 is the little brother of ACETECH's AC6000. This chronograph does not need to hide but offers almost everything the AC6000 can. It  measures the energy (Joule, FPS, m/s) and the rate of fire ROF (RPM, RPS). FPS and ROF of the last 25 shots are saved and up to 5 BB types can be configured, which you use more often. What is the difference to the AC6000? Watch my review."