Hot Launch C523 Hot Launch C523 irons combine maximum distance and forgiveness in a traditional cavity back design. The C523 Irons are made from extremely soft 431 stainless steel, providing superior feel and performance. C523 Features: VIBRCOR Technology – VIBRCOR is a high-grade TPU strategically placed in the deep undercut pocket to create a new speed-inducing and feel-enhancing internal technology. While also creating perimeter weighting around the entire clubhead for maximum forgiveness and power and ball speed enhancement off the face. Compact Design with Sharper High Toe - A new shape for the C523 Iron features a more compact design, a thinner topline and a sharper high toe that promotes game-improvement benefits in a classic iron. The ultra-low CG placement promotes a high launch, stability at impact and added forgiveness on off-center hits. Wide Sole / Deep Undercut Design - & The wide sole of the C523 Iron and its deep 360-degree undercut cavity is optimized for playability, turf interaction and ease of launch. The wider sole of the C523 offers superior bounce and increases launch for cleaner, high-flying shots. The wider sole design leads to cleaner turf interaction for more consistent shot making. The 360° undercut cavity creates more face flexing and faster ball speed across the entire face. Toe Weighted Design - Advanced toe weighting has been strategically increased and made more visible in the new C523 Iron design.