... order to improve its purity. Among the 9 products, DP IV is made by mono-crystal nanometer diamond and DP V ... is poly-crystal nanometer diamond.Using DP IV can minimize a surface roughness (Ra) of synthetic crystal, hardness ... , DP W0.75, DP I, DP II, DP III, DP IV, DP V. VOL: 0.25L, 1L, 5L, 20L.