Calibration tools are essential for ensuring that healthcare diagnostic ECG machines function accurately and. While the information provided does not list specific calibration tools one can buy, it outlines various services and parameters, which can hint at the types of tools required. Based on this, I can suggest categories of tools commonly used for calibrating ECG machines:

1. ECG Simulator: tool can simulate a variety of ECG waveforms and arrhythmias to test the accuracy of ECG machines.

2. Electrical Safety Analyzer: To verify that the ECG machine meets electrical safety standards.

3. Digital Multimeter: For measuring voltage, resistance, and current, useful in calibrating electronic components.

4. ** Simulator**: To simulate patient vitals' signals, not just ECG, also respiration, temperature, and so on.

5.Pressure Meter/Manometer**: To calibrate the pressure sensors that might be used in the ECG machine for patient interfacing.

6. Leakage Current Tester: To ensure that there are no unsafe levels of leakage current present.

7. Oscilloscope: For viewing electrical waveforms measuring their characteristics.

8. Function Generator: To generate different types of electrical waveforms to test ECG machine responses.

9. Calibration Software: Used alongside hardware to calibrate and adjust the software algorithms within the ECG machine.

10. Precision Resistors: To provide known resistance values for verifying the accuracy of measurement circuits.

When choosing calibration tools for ECG machine hardware, it's important to consider the specific calibration requirements of the machine you are building. For precise models, you would typically need to contact suppliers or check with professional healthcare equipment providers who specialize in calibration tools. The brands and specifications of such would depend on the accuracy required, the features of the ECG machine, and the relevant standards that the machine must comply with. Manufacturers like Fluke, Tektronix, Keysight, and Philips offer relevant equipment and tools suited for such delicate calibration tasks. Always ensure that the tools you purchase meet the international standards and are approved for use in calibrating medical diagnostic devices.