Yes you can, just add up to your pledge to cover for the number of units you want. Only constraint is that they should all be shipped to the same address.
For example, for the Bellafit rewards ($80)
- 2 Bellafit would be $160+Shipping cost
- 3 Bellafit would be $240+Shipping cost
- 4 Bellafit would be $320+Shipping cost
When the campaign ends, you will receive a survey where you will be able to select the number of units, color, model, size...