Shires flexi rein shires flexi rein is a rein attachment with an elastic insert that helps relieve any tension and pressure the flexi reins is design allows the horse to flex at the poll and neck encouraging him to relax as the update of the contact with the elastic helps eliminate pulling jogging head tossing and snatching of the reins as it relieves the pressure two levels of adjustment the first for general schooling and hacking the second for faster work or stronger horse