AP5 ultra-thin polymer windows are the highest performing x-ray windows available for low and high energy x-ray analysis. AP5 windows are ideal for applications that require maximum transmission of low energy x-rays, high mechanical strength, light rejection, vacuum tightness, reliability, and increased solid angle. AP5 windows are used in applications where high temperature, light element detection is important and beryllium windows are ineffective. AP5 windows can be used in all applications where AP3 windows are used.