Phillips 66 X/C Aviation Oil is a leading multi-grade engine oil formulated for year-round use in aircraft piston engines. It provides performance benefits compared with single-grade oils, including easier starting and faster oil circulation at low temperatures, reduced warm-up time, and reduced oil consumption in most engines. Both the 20W-50 and 25W-60 viscosity grades are recommended for use during break-in and then as the operational oil until TBO. Purchase X/Chereand receive free shipping.