6 Collar Ferrule OD .55" fit Callaway CF 16 17 19 Big Bertha Apex Epic .370 "
No bubbles after ferrule turned or cracks during the installation. Fits Most of late Callaway irons after 2015 with. 370" hosel. Apex forged, CF-16, XR, Epic, SteelHead iron. 6single Silver Ring Easy Install Collar Iron Ferrules.