Propeller hubs use the common Rotax pattern (6 bolts (5/16″ or M8 bolts) on a 75 mm circle.
*Note: all PUSHER FAN setups using Kohler, Briggs, Honda, Predator, or similar engines use a left-hand propeller. Otherwise, to determine whether you need left-hand or right-hand blades, imagine sitting DOWNWIND of the propeller (i.e. behind the craft for a pusher installation, or in the cockpit for a tractor installation). If the propeller will be turning COUNTERCLOCKWISE, this is a LEFT-HAND propeller. If the propeller will be turning CLOCKWISE, this is a RIGHT-HAND propeller.
Remember that gearboxes reverse the propeller rotation direction and belt reduction drives do not.