MainFrame XL Face MainFrame XL Face Technology uses a variable thickness pattern that maximizes flex at impact to boost distance. It also repositions weight low and deep in the clubhead for added forgiveness and consistency. GlideRail Our proprietary GlideRail Technology gets a new, optimized design to deliver cleaner, uninterrupted swings through the turf. Three rails along the sole of the club help keep the face straight through impact. XL Head Design With an improved XL Head Design packing even more MOI than last generation, plus a low-and-deep weighting profile, players can enjoy long, high-launching ball flight with plenty of forgiveness. Rebound Frame Instead of giving it one flex zone, we’ve got two. With alternating flex zones acting in-sync, Rebound Frame directs more energy into the ball for speed and distance on every shot.