The listed power measuring heads working according to the thermoelectric principle. That means that the through radiation created heat will be tranformed directly into voltage.
Series HP
Pyroelectric power measuring heads with ceramic absorbing layer
The measuring heads from series HP are provided with a ceramic absorbing layer which allows high energy and power densitys (also in a short wavelength range). The HP 25 S measuring head is especially designed for the service. With a compact housing it is comfortable to transport but allows high power only for a short time cause of its small cooling surface.