Callaway Mens Big Bertha OS IronsExo-Cage Golf Irons Unlock More Distance The new Big Berth OS golf irons bring Callaway's revolutionary club head construction, the Exo-Cage, to irons for more distance in a whole new way. Exo-Cage Technology is a super strong chassis made with incredibly lightweight material, allowing Callaway engineers to place weight in strategic locations for greater forgiveness. This also works in tandem with the next generation of 360 Face Cup technology to function more efficiently for faster ball speed and greater distance. You get faster ball speeds across the entire club face which means more distance with every swing of your irons. Callaway's Standing Wave technology is now loaded with tungsten to lower the CG, while progressive center of gravity in each golf iron gives you optimial launch, distance and control with every club in the iron set.Callaway Mens Big Bertha OS Irons features: * Set Composition: #4-AW * New Exo-Cage Technology is lightweight and strong, allowing more weight to be placed in strategic locations to increase forgiveness and club face function * Next generation 360 Face Cup technology brings club face COR up to the USGA limite for even faster ball speeds and more distance * Tungsten-loaded Standing Wave in the sole lowers the CG for higher launch with longer carry and more speed on shots hit low on the club face * Progressive CG moves the center of gravity progressively lower as you move through the set for higher launch and long carry with long irons and greater control with short irons * Stock Shafts: True Temper Speed Step 80 Steel a UST Recoil ES 460 Graphite * Stock Grip: Callaway Universal Callaway Mens Big Bertha OS Irons Club Loft Length Lie Angle Offset Swing Weight #4 20.5A 39.125" 60.5A 0.26 D2 #5 23A 38.5" 61.25A 0.24 D2 #6 26A 37.875"62A 0.22 D2 #7 30A 37.25" 62.5A 0.20 D2 #8 34.5A 36.625" 63A 0.175 D2 #9 39A 36" 63.5A 0.15 D2 PW 44A 35.75" 64A 0.125 D2 AW 49A 35.5" 64A 0.10 D2 SW 54A 35.25" 64A 0.10 D2