The pro vibe 7s 318mm puzzle stem a high performance lightweight oversized alloy stem as used by top professionals 3d forged 7075 t6 alloy cnstruction increases strength and keeps the weight down pro vibe 7s 318mm puzzle stem features innovative and secure puzzle clamp system evenly spreads load through the clamp area whilst reducing stem weight the gapless puzzle clamps interlocking design makes side movement loading impossible where traditional top bolts would be under