|Portable Skelevator/Transformation Chamber|
To change into Ghosbuster outfits on location
Tracy the Gorilla carried a Portable Skelevator/Transformation Chamber with him in his backpack that Jake and Eddie could use to change into their Ghost hunting outfits when they were allready out on location. It folded out into a perfect replica of the Skelevator, complete with a gateway to the transformation dimension.
The Portable Skelevator/Transformation Chamber was first used in the episode Rollerghoster.
In the episode The Battle for Ghost Command Tracy reveals a similar device that turns the inside brim of his fedora into a portal to the transformation area, letting him shove Jake and Eddie inside and pull them back out in their uniforms.