For the electricians and technicians out there, this YFYIQI surge protector tester is a seriously handy piece of equipment! With its touch color screen and automatic shifting功能, testing MOV arrestors and insulation resistance has never been easier. The MOV testing range goes from 0 to 2000V and 0 to 1000μA, while the discharge tube range covers 15 to 2000V - plenty of range for most professional applications. The 7.2V 2600mAH rechargeable lithium battery gives you more than 3 hours of continuous use, which is great for working in the field without power outlets. What's really convenient is the data storage - it can hold 1000 groups of varistor data, 1000 groups of GDT data, and 1000 groups of insulation resistance readings. The qualification judgment feature is smart too - it gives an audible beep once for合格 values and three beeps for不合格 ones, so you know immediately whether something passes or fails. The USB interface lets you upload all your test records to a computer for documentation and analysis. Overflow protection displays as '9999.99' so you know when you're beyond the measurement range. The whole unit comes in a protective aluminum case with all the accessories you need - test cables, crocodile clips, probes, charger, and USB cable. Whether you're maintaining electrical systems, installing surge protection, or doing quality control work, this tester makes the job so much more efficient. The automatic power-off after 15 minutes of inactivity helps conserve battery life. If you work with electrical systems and need reliable testing equipment that's both accurate and user-friendly, this YFYIQI surge protector tester is definitely worth considering. It's one of those tools that pays for itself in time saved and problems prevented.