FX135 Tuning Fork Watch Crystal Fox / Abracon FX135 Tuning Fork Watch Crystal is a SMD, ultra low profile (0.9mm) crystal with long term stability. Frequency is 32.768 kHz with frequency stability at -0.045PPM/(Δ°C) over an operating temperature of -40°C to +85°C. Fox / Abracon FX135 Tuning Form Watch Crystal is RoHS compliant and Pb-free.