Sorry if this has been posted elsewhere but if it has I can't find it.

From the ATO site:

Elite Challenger Series Unveiled: Tretorn SERIE+


Tretorn SERIE+ logoThe ATP and Tretorn®, the outdoor lifestyle brand, announced today the establishment of a premier series of 22 ATP Challenger Series tournaments to be known as the Tretorn SERIE+ (“serie plus”). The agreement makes Tretorn the umbrella sponsor of the elite series, and designates Tretorn as the Official Ball of the ATP Challenger Series worldwide.

Tretorn SERIE+ Tournament Schedule

The announcement coincides with the start of Tretorn’s long-term investment in professional tennis as the Official Ball at the Heilbronn Open in Heilbronn, Germany this week, and will continue throughout the next three years at ATP Challenger Series tournaments across the world.

“Tretorn is synonymous with tennis,” said Ulf Kinneson, General Manager, Tretorn AB. “As the brand continues its revival and growth, it was important to keep the connection to Tretorn’s tennis and sporting heritage in a meaningful and impactful way. We know the SERIE+ is going to be a big hit with tennis fans.”

The 22 premier ATP Challenger Series tournaments – all with prize money of $100,000 or greater – will be part of the SERIE+, unifying an elite series of tournaments across much of Europe, as well as Asia and North Africa. Much like the ATP Masters Series has done with top-tier ATP tournaments, the SERIE+ will provide cohesive branding to each event and will honor the SERIE+ season-long champion at the end of the year.

Laurent Delanney, Senior Vice President, ATP Properties, said: “To partner with a traditional brand like Tretorn with such great tennis history as an umbrella sponsor of the Tretorn SERIE+ is an important milestone for the Challenger Series. The popularity and investment in pro tennis continues to grow worldwide – at all levels and in all markets – and we welcome Tretorn as the Official Ball of the Challenger Series.”

The Tretorn SERIE+ will provide the platform for Tretorn’s re-entry into the performance tennis ball market with the SERIE+ ball having undergone considerable testing over the past year at several ATP Challenger events.

“Tretorn SERIE+ tennis balls are the very best in the world,” said Swedish touring pro Joachim Johansson, a former top 10 player and US Open semifinalist.
2007 Tretorn SERIE+ Tournament Schedule*
Week starting Tournament Prize money
22 JAN HEILBRONN, Germany $100,000
05 FEB WROCLAW, Poland $125,000
30 APR TUNIS, Tunisia $125,000
07 MAY PRAGUE, Czech Rep. $125,000
11 JUNE LUGANO, Switzerland $100,000
02 JULY CORDOBA, Spain $125,000
09 JULY SCHEVENINGEN, Holland $100,000
23 JULY POZNAN, Poland $100,000
06 AUG ISTANBUL, Turkey $125,000
13 AUG HANNOVER, Germany $125,000
17 SEP SZCZECIN, Poland $125,000
01 OCT MONS, Belgium $125,000
15 OCT ANDREZIEUX, France $125,000
05 NOV BRATISLAVA, Slovakia $100,000
* More tournaments to be added