It's a 0.3uF. This surface mount technology and comes in a 0603 package. This is a small package with good temperature coefficient.  0603 Means ‚So the “06” in the 0603 package name means it is . 06 inches in length and the “03” means it is . 03 inches in width. The standard dimensions of an 0603 package are: Length: 1.55 ± 0.05 mm. Its used to store charges temporarily its mostly used in noise filtering energy storage and many other devices etc. Its the basic need of every PCB.