Circulating osteogenic precursor (COP) cells are a population of progenitor cells in the peripheral blood with the capacity to form bone in vitro and in vivo. They have characteristics of the mesenchymal stem and progenitor pool found in the bone marrow; however. more recently. a population of COP cells has been identified with markers of the hematopoietic lineage such as CD45 and CD34. https://www.roneverhart.com/Herco-Clay-Guitar-Humidifier-p23607/