/eɪ/ This diphthong is a glide from mid front tongue position toward a higher, backer position similar to that of /ɪ/.
A backer is someone who helps or supports a project, organization, or person, often by giving or lending money. I was looking for a backer to assist me in the attempted buy-out. someone who supports a plan, especially by providing money
One who, or that which, backs; especially one who backs a person or thing in a contest