Hearing Aid

1. Hearing aid

1 . 2 : Front

1 . 3 : Back

1 . 4 : Top

1 . 5 : Bottom

1 . 6 : Right

1 . 7 : Left

1 . 1 is a top, front and right side perspective view thereof; 1 . 2 is a front elevation view thereof; 1 . 3 is a rear elevation view thereof; 1 . 4 is a top plan view thereof; 1 . 5 is a bottom plan view thereof; 1 . 6 is a right side elevation view thereof; 1 . 7 is a left side elevation view thereof; The broken lines in the reproductions illustrate portions of the hearing aid that form no part of the claimed design.