Harrows Silika Dart Flights - Black Edition - Tough Crystalline Coated - Standard No6. Silika Black Edition flights are the latest addition to the unique Silika flight range. Made using premium 100 micron material and then coated in our unique Silika coating, these flights have fast become one of our most popular ranges. The tough Silika crystalline coating contains tiny particles which, once applied, provide unparalleled longevity and extreme performance. Available in No2 and No6.