The ultra-miniature 4-Pad ECX-1210B is a very compact SMD Tuning Fork Crystal. The 1.2 x 1.0 x 0.35 mm ceramic package is the smallest in it’s class. This is very popular with small wearables and medical devices. ECX-1210B 32.768 KHz SMD Tuning Fork Crystal Request a Sample ECX-1210B SMD CRYSTAL Low Power RTC Applications such as STM32 AN2867 1.2 x 1.0 mm Footprint Extended Temp. Range RoHS Compliant Applications: Smartphones, wireless modules,.