Yesterday yet another Callaway Golf driver popped up on the USGA’s Conforming Clubs List this week, and no, it isn’t the rumored next XR driver.

Sources inside Callaway described the new model as a “prototype experiment.” When asked if more details could be provided, the same source replied, “not quite yet.”

Inherent vagaries notwithstanding, there’s at least the suggestion that more information will be shared in the not too distant future, and that could suggest that the purpose for the Sub Zero V will extend beyond tour use only.

What do you think is the story behind the Rogue Sub Zero-V?

As always, stay tuned. We’ll have more information as soon as it becomes available.