Certified pros. The EPA calls for that anyone who handles or buys refrigerants immediately after 2018 be properly trained and licensed. Wholesalers that offer possibly ozone-depleting or substitute refrigerants have to keep invoices that suggest the title of the purchaser, the date of sale, and the amount of refrigerant purchased. https://buy-r407c-refrigerant46796.blogozz.com/28222023/the-smart-trick-of-buy-r407c-refrigerant-that-nobody-is-discussing