OSP is the abbreviation for Natural and organic Solderability Preservatives, also called bare copper, Entek. To put it simply, OSP is an natural skin film that grows chemically over a clear bare copper surface area. This movie is proof against oxidation, thermal shock and humidity and protects the copper floor https://8-layer-thick-copper-powe49371.blog2news.com/31612099/top-14-layer-module-pcb-circuit-board-secrets