Asicminersshop is top shelf when it comes to professionalism and customer service. I purchased a used s19 from them which worked for a couple of days then oddly the hashboards malfunctioned. Brad and the team worked extremely hard to fix the problem remotely which was astonishing but to no avail. The device was still under warranty but the manufacturer from China advised me that they did not have the parts needed to repair the device and wanted to send me totally different miners that were not profitable in my region. I did not accept the non-profitable replacements from the manufacturer. Brad and Tony both arranged to have the malfunctioned parts shipped to their repair shop and I'm happy to report that my device is functioning perfectly well. These guys went above and beyond to ensure satisfactory service. Great, Honest group over there! Will get my business every time! Thanks to Brad, Tony and the whole team at Asicminersshop.com out there in California