The Barracuda shaft from Henry Bodnik features a slim diameter (4.2 mm inner diameter), a pre-installed nock pin and a very wide spine range.
The arrow shaft has an overall length of 32 inches with round barrel 0.006
    Spine: 300, 400, 500, 600, 700, 800, 1000, 1600 and 1800
    Tolerance: +/- 20
    Inner diameter: 4.2mm