About YOYI：Us as a mature 3d filament enterprise,have strict requirements on 3d filament and always continuous improvement. Raw Materials：YOYI raw materials are imported from Europe, without any impurities, giving buyers a better experience. Strict Quality：After strict procedures, no bubbles, ultra smooth technology,little to no odor,precise precision, reaching the REACH standard. Print Suggestion：Tested for all filaments,please print according to the print temperature we provide(250℃ – 275℃). After Sale：We are confident in YOYI products. If you are not satisfied or do not meet your expectations, support free return within 30 days.