I tested the central BULLNET is 4 and the new models are by far the most efficient, requires patience to understand programming, after familiar, it can be programmed in 5 minutes, taking the time to write everything down in if that was programmed and as the detector is well turn on and reprograms cut away to reprogram the next and when your detector is not valid, well ensure that is not already registered on an area as Central does not record a detector twice already registered, so take an area for the detector test and erase on. NEW CENTRAL ARE COMPATIBLE WITH FORMER DETECTORS, MODE DEGRADE, SUCH AS OLD MAGNETIC CONTACT SOS RECOGNIZED BUT WORKS PERFECTLY IN FASHION AND HOME ALARM MODE. REMOTE CONTROLS OLD MODEL TWO FUNCTION KEYS ARE TURNING BUT WORKING WELL. PROTECTIVE FILMS ON CENTRAL MAKES APPEARANCE REMOVE OLD WHEN SHE SHINES. SMARTPHONE APPLICATION AND FUNCTION ON CAR TOP SECRET CACHE ALWAYS CODE WHILE USING.