With its traditional blade

appearance—including a thin top line, smooth hosel transition, compact head and narrow, cambered sole—the S59 quickly became our most popular iron on Tour. The S59 also featured a stabilizing bar across the cavity which produced a solid feel and distance control, and a large Custom Tuning Port (CTP) which added forgiveness on mishits and enhanced club head feel. The CG, which was located closer to the face, created the penetrating trajectory preferred by top players.

The S59 Tour model was introduced

the following year, and added a ferrule and a polished and brushed finish for a classic look.

The extremely popular G2 model,

introduced in September 2003, was available in four different models, including models designed specifically for golfers with slower swing speeds.

• G2 — with a wide sole and low center of gravity positioned away from the face, it provided higher launching, more forgiving results.
• G2 HL — the wide sole and extreme perimeter weighting of these long irons allowed golfers to hit longer, higher, softer-landing shots.
• G2 EZ — engineered for slower swing speeds, the G2 EZ loft configurations were designed to optimize yardage gaps between clubs.
• G2L — light-weight and easy-to-hit, G2 L irons were designed for women with slow swing speeds, utilizing loft progressions optimized to achieve the ideal distance between shots.

Introduced in late 2002, the i3+ Series

improved on the top selling i3 Series iron. Like the model it succeeded, the i3+ Series was available in two different models—the i3+, and the slightly smaller i3+ Blade. Key differences between the i3+ Series and the i3 Series included:

• A 15% larger Custom Tuning Port (CTP) in the cavity that increased the perimeter weighting for added forgiveness
• A larger Notched Hosel for an easier transition through the grass
• Redesigned leading edge and bounce geometry which lowered the face surface for more consistent ball contact and improved playability from a wide range of lies and conditions

The slightly larger i3+ model is for players needing forgiveness and consistency, while the i3+ Blade model appeals for players who seek the classic look and feel of a club with less offset and a smaller head.

The i3 Series was introduced in late 1999,

became the No. 1 selling iron in the U.S. in 2000, and repeated the honor in 2001*. Available in both Blade and O-Size models, the i3 Series feature several innovations that appeal to players of all levels:

• A Custom Tuning Port (CTP) in the cavity that controls vibration for improved feel and feedback
• A Notched Hosel that allows the club head to be precisely calibrated for loft and lie
• A Flat Top Hosel that increases the cross-sectional area in contact with the shaft, reducing shaft stress for improved feel

The slightly larger O-Size model has optimum offset and bounce for players needing forgiveness, while the Blade model gives better players the ability to shape and control their shots.

The ISI Series was introduced

in 1996 with the ISI (copper) and ISI-N (nickel) models. Soon after, the ISI-K (oversized stainless steel) and then the ISI (compact stainless steel) were made available.

The goal of these irons

was to combine the accuracy of the ZING 2 model with the shot-making capability of the popular EYE2 model. Our engineers achieved this goal through extreme perimeter weighting and a patented cavity design that has an ellipse and five vibration-absorbing fingers. A more rounded shape, a cleaner top line, and alignment markings on the face give the golfer confidence over the ball. The result is a club that feels solid, offers the playability that golfers need to control their shots, and is forgiving on mis-hits.

The ZING 2 iron was introduced

in January of 1994. Offering the key weighting features of the ZING iron with more rounded shape, the ZING 2 continued the emphasis on "extreme" weighting to optimize forgiveness for greater accuracy. The ZING 2's sole design not only complements the extreme weighting design, but also reduces the surface area in contact with the turf to promote clean ball contact.

Introduced in January, 1992,

the ZING iron defined "extreme perimeter weighting." The deeply indented trailing edge helped reduce the surface area in contact with the turf while further increasing the perimeter weighting.

EYE2 irons, first introduced

in September of 1982, are without doubt the most popular irons in the history of the game. This model underwent many revisions over the years, the final changes resulting in the EYE2+ model, which was introduced in April 1990.

Features and identifying markings:

• "V" groove models manufactured from 1982 through Summer 1984, identified by PAT. PENDING in cavity and KARSTEN MFG CORP PHOENIX AZ 85068 U.S.A. upside-down on back of top rail.
• Eye2 Lite models introduced in 1984, identified by PAT. PENDING in cavity and KARSTEN PHOENIX AZ 85068 U.S.A. right-side-up on back of top rail.
• "U" groove models manufactured from Fall 1984 to Fall 1985, identified by U.S. PAT. D276644 OTHERS PEND. in cavity.
• Radiused "U" groove models manufactured from Fall 1985 to March, 1990, identified by U.S. PAT. D276644 and 4.512.577 in cavity.
• Modified "U" groove models manufactured after April, 1990 identifed by dot beneath patent numbers in cavity.
• "New EYE2" models with reshaped soles, increased perimeter weighting, less bounce in wedges, and stronger lofts than the original EYE2 were first introduced in November of 1989. Identified by U.S. Pat. 4.512.577 and 4.621.813 in cavity, club heads produced before March 31, 1990 had no "+" in the cavity.
• In April of 1990, a "+" was added to the cavity, and this model became the EYE2+.