As the name implies, it's what you don't see when you stand above the Nike VR_S Covert irons that matters most.
"It's a max game-improvement iron, but it doesn't look like one," says Nike's Robert Boyd, the company's Innovation Team Leader for metal woods and irons.
The irons, designed for high-handicappers and players who want to maximize distance, have weighted sections in the heel and toe that should really help them resist twisting on off-center hits and increase forgiveness.
"By taking a lot of weight out of the face and making it thinner, we were able to redistribute it into the heel and toe, so it's got extreme perimeter weighting," Boyd says, "but it won't look like it when you are preparing to hit the ball."
A black polymer badge has been used to partially fill in the center cavity between the heel and toe, but there is still a lot of open space.
Another thing not visible at address -- the extremely wide sole, which has been beveled along the leading edge -- should help golfers who tend to hit the ball fat.
"We put a lot of work into the sole," says Boyd. "It goes through the turf very cleanly, and although the leading edge is straight, there is some curvature in the sole to help the club avoid digging."
The 3- through 7-irons are cast from a high-strength, 450-Carpenter steel to maximize ball speed for added distance. The short irons -- 8-iron through wedge -- are made from 1704 stainless steel for a slightly softer feel.
The stock shaft for the VR_S Covert irons will be True Temper Dynamic Gold metal shafts, and the clubs should cost about $699 when you see them on pro shop shelves on Feb. 1. A set with Mitsubishi Diamana Kura Kage graphite shafts will also be available for $799.