Tuning Fork DT-26 & DT-38 Series Resistance welded holder HC-49U -frequency range 1.8432MHz to 125.000MHz -operating temperature range -20oC to 70oC Resistance welded LOW profile holder: HC-49S, HC-49SMD Reduced height holder HC-49SS, HC-49SSM -frequency range 3.500MHz to 66.000MHz -operating temperature range -10oC to 70oC Crystal oscillators -TTL, CMOS/TTL, TTL/HCMOS 3.3VDC -frequency range 1.000MHz to 100.000MHz -operating temperature range 0oC to 70oC