Epson's FC-135R 32 kHz crystal unit is provided in an ultra-miniature (3.2 mm x 1.5 mm x 0.8 mm) ceramic SMD package and offers a very low series resistance (< 50 kΩ). Low series resistance guarantees fast and reliable startup for low-power applications. Epson's FC-135R is widely recommended by MCU vendors for its dependable low-power operation.