The Yashica MG-1 is a great Camera you can get for a really great price. Sadly it's using a battery that's no longer beeing produced due to it containing mercury. This adapter allows you to use a stack of 4 1,5v alkaline batteries instead of the prohibited 5,6v mercury battery. all you need besides this adapter is a spring from an old pen and the new batteries. (I will soon upload pictures explaining how to use the adapter)