Hearing aid battery holder type 312 with Keychain hole

I really liked the simplicity of this model but I need it to be on my keychain or I will for get to take it with me when I go places.  Thanks to @Bbrinck_1460947 for the initial design if you just want the box and not the additions for a keychain see his design.  Holds 4 each of 312 hearing aid batteries.