You won't be able to choose the add-ons at this stage.
But after choosing a reward level, check the Add-on Menu in the project description for the prices, and find the item(s) you want to add. Simply increase your reward by the amount including the add-on(s).
For Example, If you would like to add an Extra Titanium Smartruler (30$) to your Early Bird One(1) Aluminum Smartruler(13$), Follow these steps:
Select the Early Bird One(1) Aluminum Smartruler(13$) Reward
Adjust your pledge by $30. Total Pledge = $43
Shipping is a ONE flat fee of $7~$9 depending on your location.
And at the end of the campaign, we will send every backer a survey. In this survey, you will be able to select and confirm the add-on(s) for your reward.