Live on Skysports 2: Sun 13.00 & Mon 13.00: Warwickshire set out as 12/1 shots with Coral to retain their 2010 CB40 Trophy.
Warwickshire face Hampshire in their opening game while competition favs Somerset, 8/1 with , take on Nottinghamshire.
Sussex and Essex are both 9/1 with Blue Square while national sides Netherlands and Scotland are mighty 500/1 outsiders with Ladbrokes.
Sunday 24 April:
Durham v Scotland (13:45 BST)
Gloucestershire v Glamorgan (13:45 BST)
Hampshire v Warwickshire (13:45 BST)
Lancashire v Unicorns (13:45 BST)
Northamptonshire v Leicestershire (13:45 BST)
Nottinghamshire v Somerset (13:45 BST)
Worcestershire v Middlesex (13:45 BST)
Yorkshire v Netherlands (13:45 BST)
Monday 25 April:
Derbyshire v Netherlands (12:00 BST)
Leicestershire v Scotland (13:45 BST)
Compare all Clydesdale Bank 40 odds and bet at the best price.