This is an Edison Gem (Models B & C) 4-minute Combination Attachment in it's original box with instructions.  It consists of the gear cluster on replacement longer back rod, intermediate gear, and stud.  The instruction sheet is torn but complete.  There would have been a Model H reproducer but it is not present.  The box measures 7 1/2 inches long.

If you buy it you could either put a spare or not good H in the box for display, or you can purchase the good Model H I'm selling in the following listing. 

I will be selling a collection of phonographs, parts, accessories, and records over the next few months so please bookmark me. 

I'm always happy to combine shipping.