Check the listing for details. QT2000 Qwik-Check 2 Second Acid Test Kit Quick-Check for Refrigerants/Oils. Condition: New, Made in United States. Listed at 10.00 USD. The QT2000 Qwik-Check 2 Second Acid Test Kit by Mainstream Engineering is a quick and reliable tool for testing refrigerants and oils. Made in the United States, this acid test kit is designed to provide accurate results in just a few seconds. The QwikCheck model ensures easy and efficient testing, making it a valuable resource for HVAC and refrigeration professionals looking to quickly determine the condition of their systems.