These two types of locks are designed for completely different door setups. Your choice depends entirely on how your glass door operates and is configured within the frame.
Sliding Glass Door Lock
Choose this lock if your glass door moves horizontally along a track and locks against the surrounding frame or wall.
Glass-to-Glass Door Lock
Choose this lock if you have two hinged glass doors that meet in the middle and need to be secured to each other, with no vertical frame between them.