Frequently Asked Questions

Which is better for home use, the FNIRSI DMT-99 or the FNIRSI S1?

For general home use, I’d give the edge to the DMT-99. Its recording mode that plots 8 measured values over time is incredibly useful for diagnosing flickering lights or intermittent outlet problems, something the S1 simply can’t do. The 1500 mAh battery also lasts noticeably longer than the S1’s 1000 mAh pack. The S1 is only a better choice if you prioritize the slim electric pen form factor and built-in flashlight for quick checks in dark spots.

Is the FNIRSI S1 worth the extra money over the DMT-99?

Not for most people, honestly. The S1’s 2-in-1 electric pen design and built-in flashlight are nice extras, but the DMT-99 gives you more functionality with its recording mode, monitoring mode with custom thresholds, and a bigger 1500 mAh battery. Unless you really need that ultra-slim profile for pocket carry, the DMT-99 delivers better value for your money.

Which multimeter has a better battery life, DMT-99 or S1?

The DMT-99 wins this one hands down with a 1500 mAh rechargeable battery compared to the S1’s 1000 mAh battery. That’s 50% more capacity, which translates to a full day of troubleshooting without hunting for a charger. Both use convenient Type-C charging, so you don’t have to deal with disposable batteries on either model.

Can the FNIRSI DMT-99 measure temperature like the S1?

No, this is actually a key difference between the two. The S1 supports temperature measurement as one of its multiple functions, while the DMT-99 does not list temperature in its specs. If you need to check oven thermostats or HVAC systems, the S1 is the better pick. For everything else like voltage, resistance, capacitance, and frequency, both meters handle those just fine.

Which multimeter is easier to carry around, the DMT-99 or the S1?

The S1’s slim electric pen design is definitely easier to slip into a pocket, but here’s the twist — it actually weighs 1.1 pounds compared to the DMT-99’s 0.42 pounds. So the DMT-99 is lighter by over half a pound despite being a bit bulkier at 6.01 x 3.15 x 1.52 inches. For carrying in a tool bag, I prefer the lighter DMT-99. For pocket carry, the S1’s shape wins.

Does the FNIRSI DMT-99 have a flashlight like the S1?

No, the DMT-99 does not have a built-in flashlight, while the S1 includes one specifically for working in dark environments. This is one of those small features that makes a big difference when you’re poking around a dim crawl space or behind a heavy appliance. If you work in low light often, the S1’s flashlight is a real convenience you’ll appreciate.