All listed coils are made of copper lacquer wire with a purity of > 99.995%. The wire ends are tinned and labelled. Inductance is measured at 25 degrees Celsius; tolerance is +/- 3%. L denotes inductance, R the DC resistance, D the diameter, Le the length, W the width, H the height.
Air coils (i.e. coils without a ferro-magnetic core) are absolutely distortion-free, which on the face of it makes them ideal for all audio applications. The trouble is, their electrical resistance increases with their inductance. There are two solutions to this problem: One can either use very thick windings (this is why our standard range includes windings with wire up to 3 mm in diameter) or coils with cores. Lower cost and smaller size are also common reasons for choosing cored coils.