Harrows Black Jack Darts – Stainless Steel Darts. The Black Jack range is a sleek and menacing series for the advancing player. The tungsten look barrels feature precision black knurling for maximum grip and optimum control. The barrels are teamed with the very latest advances in shaft and flight technology.Harrows Black Jack Darts – Stainless Steel Darts. The Black Jack range is a sleek and menacing series for the advancing player. The tungsten look barrels feature precision black knurling for maximum grip and optimum control. The barrels are teamed with the very latest advances in shaft and flight technology.Harrows Black Jack Darts – Stainless Steel Darts. The Black Jack range is a sleek and menacing series for the advancing player. The tungsten look barrels feature precision black knurling for maximum grip and optimum control. The barrels are teamed with the very latest advances in shaft and flight technology.Harrows Black Jack Darts – Stainless Steel Darts. The Black Jack range is a sleek and menacing series for the advancing player. The tungsten look barrels feature precision black knurling for maximum grip and optimum control. The barrels are teamed with the very latest advances in shaft and flight technology.