All 4 pens are basically the same device with the following exceptions.
- The Classic & cmodels have UV lamps that will last 8,000 treatments (either 1/2 or full 1 liter treatments) and a 3 year warranty.
- The Traveler & Emergency models have a UV lamp that will last 3,000 treatments and a 1 year warranty.
- Traveler & Emergency pens do not come with batteries included and the Classic and Defender models come with 4 AA Lithium batteries included.
- The Defender is manufactured to meet US Military specifications regarding manufacturing & assembly.