From Fair-Rite, these ferrite rods are for use in RFID (Radio Frequency IDentification) and antenna applications. The 78 material is recommended for 125kHz applications, and 61 material is recommended for 13.56MHz applications.
Type = Antenna & RFID Rods
Dimensions = 4 (Dia.) x 30mm
Application = Inductive Component
Diameter = 4mm
Height = 30mm