🌡️ SONOFF WTS01 — Waterproof Temperature Sensor Probe (RJ9, for TH Series)
Measure temperature in wet, outdoor, and extreme environments. The DS18B20 is a stainless steel waterproof temperature probe that plugs into the RJ9 port on any SONOFF TH controller. Measures from -55°C to +125°C — ideal for geysers, pool water, pipe temperatures, cold rooms, and outdoor installations. 1m cable. Extend up to 60m with the optional RL560 extension cable. MPN: DS18B20.
Choose your TH sensor (RJ9 connector):
⚡ Key Features
- Waterproof Stainless Steel Probe — fully submersible; use in water, on pipes, outdoors, or in any wet environment
- Wide Temperature Range — measures -55°C to +125°C; suitable for freezers, cold rooms, geysers, and even industrial applications
- Temperature Only — dedicated to accurate temperature measurement (no humidity); ideal when you need reliable temp data in harsh conditions
- RJ9 Plug-and-Play — plug into any SONOFF TH controller's RJ9 port; recognised instantly
- 1m Cable Length — mount the probe directly on pipes, inside tanks, or in water
- Extendable to 60m — use the optional RL560 RJ9 extension cable to reach remote locations
- Rust-Resistant — stainless steel construction resists corrosion from water and chemicals
🏠 Use Cases
Geyser Control
Strap or mount on your geyser outlet pipe. Set auto-mode to maintain 55°C. The TH controller switches the element off when the target is reached — saving electricity daily.
Pool Temperature
Submerge in your pool to monitor water temperature. Log data over 6 months via the app. Know exactly when the pool is warm enough for a swim.
Freezers & Cold Rooms
Monitor freezer or cold room temperature and get alerts if it rises above a safe threshold. Protect food and stock from spoilage.
Outdoor & Pipe Monitoring
Mount on water pipes to monitor for frost risk, or outdoors for weather station data. The waterproof design handles rain, sun, and temperature extremes.
🔗 Compatible TH Controllers (Required)
The DS18B20 requires a SONOFF TH controller. The sensor plugs into the RJ9 port on the TH unit.
SONOFF TH Elite 20
20A smart switch with LCD display, 6-month history, and RJ9 sensor port. The premium TH controller.
View Product →SONOFF THR320 Origin
20A smart switch with RJ9 sensor port. Same power as the Elite, without the LCD.
View Product →SONOFF THR316 Origin
16A smart switch with RJ9 sensor port. Most affordable TH controller.
View Product →📋 Technical Specifications
| Product | SONOFF DS18B20 Waterproof Temperature Probe |
| MPN / Model | DS18B20 |
| Measurement | Temperature only |
| Temp Range | -55°C to +125°C |
| Temp Accuracy | ±0.5°C (within -10°C to +85°C) |
| Probe Material | Stainless steel (waterproof) |
| Connector | RJ9 (4P4C) |
| Cable Length | 1 metre |
| Extendable | Up to 60m with RL560 extension cable |
| Power Supply | 3.0–5.5V (powered by TH controller) |
| Compatible With | THR320 · THR320D (Elite) · THR316 |
| Warranty | 1 Year Manufacturer Warranty |
❓ Frequently Asked Questions
Can I submerge it in water?
Does it measure humidity?
How do I mount it on a geyser pipe?
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Waterproof. Accurate. -55°C to +125°C.
Stainless steel temp probe for geysers, pools, pipes, and outdoor.