An apparatus for use in testing a protective mask for leaks. The apparatus includes a test head assembly for supporting at least a portion of a protective mask to be tested for leaks. The test head assembly may be freestanding or it may be mounted directly on the mask tester. Preferably, the test head assembly includes a test head having a test space. The test space is operably associated with a mask tester such that a fluid from the test space is directed to the mask tester for analysis to determine if a leak exists in the mask. The test space is generally coextensive with the inner surface of the protective mask being tested. Although the test space is generally coextensive with the inner surface of the protective mask being tested, it is designed such that it has minimal volume to enhance the testing process by expediting test response time, reducing the time period it takes for a mask tester to reach one or more prerequisite test conditions (e.g., a predetermined vacuum), eliminate or greatly reduce lag time when the mask tester is operating in the probe mode (i.e., the mode used to isolate the location of a leak) and prevent dilution of challenge concentration. Preferably, the test is shaped to permit a protective mask to be readily mounted on the test head in a fluid tight manner. Preferably, the test head is formed from two or more removable sections to allow the size of the test head to be readily modified without replacing the entire test head. An optional perfect mask or test shroud may be mounted about the test head to ensure that the mask tester is not erroneously detecting leaks in a protective mask being tested.