As our testing videos evidence, the use of one (1) Zeppelin can deter sharks (even multiple sharks), when rigged correctly.
However, depending on your line weight, bottom fishing method, and target fish species, if you are able to attach two (2) or more Zeppelins to your line, so you have one unit placed 6-10" inches (15-25 cm) above your catch, and a second unit also placed 18-24" inches (45-60 cm) below the tail of your catch, then you will increase the effectiveness and deterrent field. However, if you are using multiple Zeppelins, you do not want them to stick to one another. This will cause tangling and diminished product effectiveness.
The use of multiple Zeppelins has been proven effective in a Hawaiin commercial bottom fishing study with 10+ hook sets.