The inaugural Royal London One-Day Cup, county cricket's new 50-over competition, gets under way on Saturday.
The event replaces last season's YB40 - won by Nottinghamshire - with Lancashire hosting Roses rivals Yorkshire, Glamorgan taking on Middlesex and Hampshire visiting Derbyshire.
The move from 40 overs to the 50-over format is intended to bring the domestic scene in line with the one-day international game.
All 18 County Championship sides will take part, initially in two randomly drawn groups of nine with the top four teams from each group progressing to the quarter-finals, which begin on August 26.
"It's a bit of a change up from last year - new format, new fielding restrictions, two new balls - basically reflecting international 50-over cricket and we're all excited to get started," Nottinghamshire's Harry Gurney, who has played six one-day internationals for England, told Sky Sports News.
"In the international game there's the India series, then the Sri Lanka tour around November time and the World Cup on the horizon so it's a great opportunity for everyone involved in the county game to concentrate on the 50-over stuff and try to stake a claim for those squads.
"I'ts quite well-timed: the selectors will be coming together and for guys with international aspirations, they've got the opportunity to knock the door down over the next few weeks."
Lord's will host the competition's final on September 20.
Unlike the YB40, the competition will not feature the Netherlands, Scotland or the Unicorns, a side made up of players without professional contracts.