Callaway's number one goal for the FT-i during the design of the FT-i is what they call the Complete Inertial Design. The goal being to maximize the moment of inertia for the driver head so the ball flies straighter minimizing slices and hooks. Callaway designed the club to have the weight distributed around the edges of the head and away from the center of gravity. Callaway claims that this distributed weight approach expands the club's sweet spot so even if you hit the ball on the edge or corner of the face, you'll still have a straight shot.
A classic Titanium material was tested, but Callaway claims that an all-Titanium head would not distribute the weight properly giving a maximized impact surface. Using their previously successful Fusion Technology, which is the mixture of more than one material, Callaway claims they were able to successfully obtain the proper weight distribution.
FT-i Models
Standard FT-i: Fujikura Speeder 586 shaft
FT-i Tour: open faced, which is preferred by elite golfers, and a Fujikura Speeder 686 shaft
Women's FT-i: Fujikura Sakura shaft