http://en.wikipedia.org/wiki/Bully_stick
Check the above link...
Bully Spring is a small part of the bully stick (I THINK?), coiled up like a spring and about 8 inches long coil....
Available at Petsmart, and Petco.
BTW, Jackio is NOT crazy about the Royal Canin, she eats some only if covered with melted cheese. Back to the search .... picky...picky.......
Jackio