Caliburn The Rock Darts – Steel Tip – 90% – Black & Red – 21g. This Caliburn The Rock Steel Tip Dart features a 90% straight tungsten barrel, with a triple ring grip along the length of the dart. The black and red coating enhances the visual appeal of the dart. They come complete with Caliburn Dart Shafts and Flights.Caliburn The Rock Darts – Steel Tip – 90% – Black & Red – 23g. This Caliburn The Rock Steel Tip Dart features a 90% straight tungsten barrel, with a triple ring grip along the length of the dart. The black and red coating enhances the visual appeal of the dart. They come complete with Caliburn Dart Shafts and Flights.