HC49US-FF3F18-16.0000 is a crystal oscillator manufactured by Abracon. This oscillator has an HC-49US SMD package, a frequency of 18.0000 MHz, and a tolerance of ±20 ppm (parts per million). The supported modes are HCMOS and TT, and it has an operating temperature range of -40°C to 85°C. It requires a supply voltage of 4.75V - 5.25V DC.