professional's choice magnetic poll piece large 24" professional's choice professional choice magnetic poll piece the magnetic poll pieces attach easily to headstalls and halters behind the ears and has a unique rubber backing to prevent slipping. helps promote a calming and anti-inflammatory effect. can be used prior to an event to help relax a nervous horse and promote a more focused performance. it is also helpful with bad stall habits, can ease discomfort from tmj as well as teeth grinding. sizes: 17" or 24". manufacturer 30-day money back guarantee/six month warranty or as required by law.