DVFN240 is the standard model of thermal resistance tester. This tester is used at many semiconductor factories and companies all over the world. It has 200V, 40A, and forcing power is 800W at maximum.DVFN240 is the standard model of thermal resistance tester. This tester is used at many semiconductor factories and companies all over the world. It has 200V, 40A, and forcing power is 800W at maximum.