Principle of Operation:  Reflective film stretched across a rigid 4’ diameter ring.  Integral hand pump/handle
assembly creates a vacuum inside the ring, causing the reflective film to form into a smooth concave mirror that
focuses light into a 4-6” spot.

Physical:
Mirror Diameter-                        45”
Reflective Surface                     Aluminized Polymer Film
Reflective Area                         11.5 Sq. Ft.
Weight                                       8-10 lbs., depending on configuration

Performance:
Point Focus
Focal Length                            Variable, from 10' to 20'
Minimum Focal Area                4”
Time to Boil 48 Oz. of Water    15 minutes (at 900 w/msq. sunlight intensity)
Vacuum Hold Time                    minimum of 2 hours- always cover dish when not in use
Maximum Heat Flux                   850 F   
A Better Focus Co.
Product Specifications
U.S Patent # 7,374,301