The laser cone radiometer RLC60 V1 was developed in 1991 for measurements of CO2 and YAG laser high power. At the time it already had a capacity of 12kW continuous absorption for an opening of 60mm. Its working principle is that of a real calorimeter with continuous measurement of laser energy absorbed and evacuated per time unit through a water cooling. For that it is equipped with two sensors: a water turbine that measures the flow of water that cools the calorimeter shaft and a thermopile that measures the temperature difference between water at the entry and water at the exit. This system has been widely used in automotive, aerospace and nuclear industries. It was interfaced to production laser machines through its 0-10V analog output and its protection relay that triggers for insufficient cooling. Although this version is obsolete, given the depletion of stocks of Intel microcontrollers that fit the electronics, Laser Metrologie still ensures its maintenance for customers who use it.