The Vision Metron 4D Flat road bike handlebar combines the excellent ergonomics and aerodynamics of the Metron 4D, with a lower hand position and an innovative optional Modular Aero System (MAS) that can be mounted directly with clip-on system for extra versatility (not included as standard). The Vision handlebars are the ones that Team Visma | Lease a Bike also trains, rides and wins with.