You are purchasing 2 sensors that were removed from Parts shelf after decommissioned. They were on parts shelf ready for installation. I will gauratee one, but you recieve two for price of one!!! I am disabled veterans business and appreciate your patronage, you have 7 days to test both units. That is bench tesst , I am a faciluity engineer and it will only take one day to bench test , but I give you five. If it fails contact me and I will refund for One unit, the second is bonus!!!! Thanks for your patronage. Buyer pays 26 US priority mail shipping! Overseas okay through shipping only and no returns for any reason.