20/40 used in North Dakota 1.Passed ISO & API 2.Tested by Stim-Lab & Frac ... , 8-16 mesh, 12-18 mesh, 12-20 mesh, 16-20 mesh, 16-30 mesh, 20-40 mesh, 30-50 mesh, 30-60 mesh ... , 40-60 mesh, 40-70 mesh, 70-140 mesh, etc.Moreover, we ... .86631067 Fax:+86.387.86631068 www.toproppant.com NO.4 20/40 used in North Dakota