All-in-one safety testers are multifunctional devices used to perform a variety of electrical safety tests, including insulation resistance, grounding resistance, and withstand voltage testing. They are used in applications such as product certification, quality control, and electrical maintenance, providing comprehensive and reliable safety testing. All-in-one safety testers offer features such as multiple test modes, digital displays, and automated testing, making them essential for ensuring the safety and compliance of electrical products and systems. Their ability to provide comprehensive safety testing makes them valuable for maintaining electrical safety and quality.