While the original spec for Humbucker bobbins was black, a shortage of these items on the production line in the 1950s resulted in bobbins being sourced in virgin material (ivory coloured plastic), hence when guitarists started to remove their brass covers, they discovered that some guitars contained what have become known as Zebra pickups. Some people believe these are the best sounding double coil pickups ever. Trev just think they look great, and by using the same windings as the WVC pickup, they are as authentic sounding as anything currently available.
About Wilkinson
Known throughout the world as a guitar 'guru' (a moniker he tolerates rather than endorses) Trev Wilkinson's comprehensive range of replacement guitar parts are what cemented his reputation throughout the industry with their simplicity, durability and problem solving designs.