Hi David
Look here
http://www.star-board.com/2010/products/products_designdetails.php and here
www.star-board.com/2010/products/products_accessories.php scroll down to accessory bag
Would suggest they are 7x32mm
JP usually come with two sizes one small (gauge) for initial installation, then a larger gauge for when after constant changing of positions, the footstrap holes become slightly oversize - always avoid using those unless the smaller ones are problamatic - Chris at WSnS says the bigger ones are usually used buy rental fleets/schools.
Cheers