Used coralbox Wi-Fi Doser. Used for about 6 months. Comes with check valves from amazon. I found that putting check valves on the end of the dosing tubes resolved my issues with this Doser’s lines staying primed. Comes with Doser, 4 check valves, original tubing (that I didn’t use), instructions (I followed a YouTube video for setup), calibration tube and original box. I’ve had no issues with this Doser other than the lines staying primes as others have reported about this Doser. I was able to remedy that with the check valves from amazon. $125 shipped.