As far as I know, the early reactive Grooves came in 3 "strengths" - the strongest being close to today's PG pearl with PK17, and it was called the "Groove III Dynamic Reactive". Brunswick rates the III weaker than the PGs (take a look at their comparison chart - the GIII is rated F15 on the chart, the current PGs at G13, which means slightly sharper hook on a little more oil).
The Groove II was much like today's Dry/R, and the old Groove Urethane (the single blue color one) was also rated much smoother than today's one, even though I wonder why?
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DizzyFugu - Reporting from Germany
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