The ERC II was Callaway's forged-titanium driver built to exceed the USGA's spring-like-effect (COR) limit, and it became one of the biggest equipment controversies in golf history. Announced in October 2000 with limited shipments beginning early 2001, its thin, thermoformed titanium face was engineered to flex more than the rules allowed, producing extra ball speed the USGA measured as a genuine trampoline effect. Callaway chose to sell it in the U.S. anyway for recreational play, triggering a public fight with the USGA, a widely covered CNN Money story on how the 'outlawed' status boosted sales, and a position paper from Arnold Palmer on whether amateurs should use non-conforming clubs.

Independently documented by CNN Money ('Outlawed driver boosts sales'), ESPN, Golf Digest, and Callaway's own press releases as a genuine cultural flashpoint — non-conforming status drove a sales spike rather than suppressing it, and the club remains referenced today (including in modern head-to-head YouTube comparisons against current Callaway drivers) as the emblem of the early-2000s COR wars.

A collector or recreational golfer who plays only casual, non-competitive rounds and wants a piece of golf-equipment history to hit; not legal for any USGA/R&A-sanctioned competition or handicap-posting round, which rules it out as a primary gamer for club or league play.

• Announced by Callaway on October 18, 2000 as the 'ERC II Forged Titanium Driver,' with the company calling it its hottest and most forgiving driver ever made.
• Ruled non-conforming by the USGA for exceeding the spring-like-effect (COR) limit under the 1998 pendulum test, while remaining legal under R&A rules used outside the U.S. for years afterward.
• CNN Money reported in April 2001 that the driver's 'outlawed' notoriety was boosting Callaway's sales rather than hurting them.
• Arnold Palmer published a position paper addressing whether recreational golfers should be permitted to use non-conforming clubs like the ERC II.
• ERC stands for Ely Reeves Callaway, the company founder's name, tying the driver directly to Callaway's own brand identity.

Part of the early-2000s COR controversy alongside other high-COR Japan/limited-market drivers; the USGA's 1998 pendulum test for spring-like effect made it and similar hot-faced drivers non-conforming, a rules fight that shaped equipment regulation into the mid-2000s. Modern conforming equivalents from Callaway are the Epic/Paradym/Ai Smoke lines.

Realistic 2026 private-party/eBay pricing is low, roughly $40-$90 for a clean head with stock shaft, reflecting its status as a non-tournament-legal novelty rather than a performance upgrade; prices are driven by collector/nostalgia interest, not playability demand.