"Thanks to high-grade carbon shafts, premium components, and sophisticated manufacturing processes, Altra Arrows Centrum Limited 246 Arrows deliver top-flight accuracy and superior consistency. Sophisticated construction using a proprietary blend of high-modulus carbon that features NO SPINE Technology for improved tunability and reliable arrow-to arrow uniformity. State-of-the-art measuring equipment verifies arrow shaft and component straightness up to .003"" for precision. Centrum Limited 246 arrows include inserts and nocks. Weight Tolerance: 1 grain. High-modulus carbon shafts and premium components Top-flight accuracy with superior consistency NO SPINE Technology for improved tunability Straightness .003"""