1. show the prototype that you have been working on.
2. tell what you are going for, with the project.
3. tell them their money will be used for an actuall product insted of a prototype.
PS. this is for after the prototype is done, i know that it may take a long time to finish the prototype, but when you are ready for a kickstarter please remember the things i wrote in this post
Thanks, _Yopasp