The AIAC-4125C-R491J-T from Abracon LLC is a RF Inductor with Inductance 0.491 µH, DC Resistance 0.04 Ohms, DC Current 2 A, Self Resonant Frequency 400 MHz, Operating Temperature -40 to 125 Degree C. Tags: Air Core Inductor. More details for AIAC-4125C-R491J-T can be seen below.