Cobra 3DP MB Irons RHCobra 3DP MB Irons RH 3D Printed Technology With More Forgiveness The Cobra 3DP MB irons utilise 3D printing technology to combine the look and feel of a traditional forged muscle back with the forgiveness of a cavity back iron. The MB has captivated Tour players by checking all the boxes and exceeding expectations with its exceptional stability and feel. Printed from 316 stainless steel, the 3DP MB features a thinner topline with enhanced offset.