Clip-on works to repel mosquitoes.

Evaluation of commercial products for protection from mosquito bites. 

"...The personal diffusers: - OFF!(®) Clip-On™ and Terminix(®) ALLCLEAR(®) Sidekick - provided superior protection compared with all other devices in this study. These diffusers reduced biting on the arms of volunteers by 96.28% and 95.26% respectively..."

http://www.ncbi.nlm.nih.gov/m/pubmed/23092689/?i=7&from=cinnamon%20comparative