German WWII era 6x30 binoculars.  They are made mostly of bakelite and are very difficult to find.

The maker was Emil Busch AG, Optische Industrie, Rathenow (secret code cxn), a premier optics

maker.  The optics are clear.  The case was made by ux?, an unknown maker as far as I know. 

The "4" on the case exterior is likely the year of manufacture.  This set is in excellent condition.