Offset originated in putters to help golfers get their hands ahead of the ball at impact. Offset irons and woods can be helpful to golfers who slice because they provide just a split-second more time to get the clubface square before impact.
The amount of offset varies depending on the target audience for the clubs in question, from none in clubs intended for better players, to 3/8-inch or even a quarter inch in super-game improvement clubs targeted at high handicappers who slice.
For more discussion of offset, see the FAQs:
What is offset?
Will offset clubs help my slice?



