When Identifying an L-500 from the Bill Lawrence Pickups (Classic) period, you should be aware that the L-500 product line underwent name changes throughout 1981, The hot L-500L was renamed the L-500XL with the cleaner L-510L becoming the new L-500L. the L-500R did not change in output or name.

The L-500C was born in 1994 when Bill Lawrence(Willi Lorenz Stich) reintroduced the L-510R, renamed to go along with the 1981 naming changes.By Bill Lawrence (WS).

Also of note some Bill Lawrence Products (EZ) electric guitar pickups may feature the color of the pickup in the model name. For example a L-500XLZ would be a L-500XL in zebra, and a L-500RC a L-500R in cream.

I've seen some Bill Lawrence Products (EZ) pickups available online with odd naming like XL500 or XL-500. I'm not sure if this is the work of Jzchak 'EZ' Wajcman and company or a retailer of their products.

Measurement in Henries of the inductance of a electro magnetic guitar pickup.