The economical choice. Shim-pack GWS C18 is packed with high-purity silica gel. A uniform pore size ensures low pressure, while complete end-capping makes it possible for analysis of acidic or basic compounds. Bonded Phase: Octadecyl Groups, Particle Size: 5 ?m, Pore Size: 10 nm, Surface Area: 450 m2/g,Carbon Loading: 9.5 %, End-capping: Yes, pH Range: 2 to 7.5, USP Code: L1