The Mizuno JPX Fli-Hi is referred to by Mizuno as a Direct Long Iron Replacement (DLR). Designed to take the place of difficult-to-hit traditional long irons, the JPX Fli Hi uses the same specs as a long iron but with Mizuno's Hot Metal face and MAX COR Pocket Cavity. Both features help to increase ball speed from anywhere on the face, resulting in improved forgiveness and explosive distance.

The wood-type hybrid provides a larger sweetspot and lowers the Center of Gravity, making the Mizuno JPX Fli Hi easier to get in the air compared with a standard long iron. Added forgiveness is offered thanks to the Speed Bevel Sole Design and optimal face bulge and roll, that provide maximum head speed through the turf and help to correct mis-hit shots.

The JPX Fli-Hi was designed to utilise a Interchangable Shaft System (ISS) that allows golfers to experience Mizuno's innovative Performance Fitting System (PFS) in finding the shaft that is specific to their game.