The Superdrive Micro Arrow Shafts by Eason Archery are purpose-built tournament-grade arrow shafts, perfect for outdoor tournament shoots from target to field to 3D competitions. With the ultralight material coupled with the small 4mm micro-diameter, these arrow shafts provide excellent long-range shooting. Features: 4mm Tournament-Grade compound and recurve arrow shaft Multi-layer wrapped 100% carbon-fiber 4mm parallel design Specifically engineered for outdoor competition Weight tolerance of +/- 1.0 grain Straightness +/- .002-inches Recommended Components (Sold Separately): 4mm ML Stainless Steel Point 4mm Microlite Nock 4mm Pin Easton Pin Nock 4mm G Nock Easton G Pin Nock Available Spines (Weight): 350 (8.1 gpi) 375 (7.4 gpi) 425 (6.8 gpi) 475 (6.4 gpi) 525 (6.1 gpi) 575 (5.9 gpi) 625 (5.7 gpi) 675 (5.6 gpi) 750 (5.5 gpi) 850 (5.3 gpi) 950 (5.1 gpi)