ECS-40-18-10X is a miniature tubular high-frequency quartz crystal designed for cost-effective, reliable frequency control applications. While the datasheet primarily documents the ECS-3X10X and ECS-3X9X product families, the part numbering guide indicates that ECS-40-18-10X follows the ECS naming convention with frequency code 40 (4.0 MHz), load capacitance of 16 pF, and 10X package type. These crystals feature outstanding shock and vibration resistance, excellent aging characteristics, and wide frequency range capability. The devices are RoHS compliant and Pb-free, with typical operating temperatures from -10°C to +60°C and storage temperatures from -40°C to +85°C. Applications include consumer electronics, telecommunications, and industrial timing circuits where miniature form factor and environmental robustness are essential.