The CJ16-184321010B20 with SMD2016-4P Crystals ROHS manufactured by Changjing Electronics Technology is a four-pin surface mount crystal package. It consists of two miniature quartz crystals contained between an inertial steel enclosure with 4 (SMD2016) gold-plated pins. The crystals are used to create accurate frequencies, which are used across a variety of digital and analog electronic circuits such as oscillators, frequency synthesizers, VCOs, and so on. The 4-pin package is plated in gold to prevent corrosion and provide electrical conductivity. The package is RoHS compliant, meaning it contains materials deemed safe under European chemical regulations. The Changjing Electronics Technology crystals are highly reliable and low cost.