Each value corresponds to a separate inductor, no series or in parallel. Tolerance +/-10% inductors, 1uH to 1000uH total 37 values. 4mm banana sockets with plugs, easy to connect wires. High quality FR4 glass fiber PCB. Programmable Inductance: 1uH to 1000uH, E12 standard total 37 values. This is "inductance substitution box" good low-cost alternative solution, can flexible and quick setting inductance range from 1uH to 1000uH, E12 standard total 37 values. for educational experiments, electronic engineering design or test trimming are excellent applications. Features: Each value corresponds to a separate inductor, no series or in parallel. Tolerance +/-10% inductors, 1uH to 1000uH total 37 values. 4mm banana sockets with plugs, easy to connect wires. High quality FR4 glass fiber PCB. Programmable Inductance: 1uH to 1000uH, E12 standard total 37 values. Inductance Tolerance: +/-10% PCB Size: 89.6 x 64.2mm / 3.53" x 2.53"