Inkbird Bluetooth Temperature & Humidity Sensor Recorder $25.99 Delivered @ Inkbird eBay

This bluetooth sensor has built-in probe. It's Bluetooth and supports app.
You could check temperature and humidity on the app. What's more, it comes with an external plastic probe. It's great if you want to check the temperatures of liquids like aquarium temperature.

Features

Free iOS and Android APP to monitor temperature and humidity any time
APP support multiple languages
Smartphone support limited to 6 sensor connections at one time
Support external probe and data record interval can be adjustable
Support for application scenario selection and addition
Alarm and data history view available
Temperature unit switching (°C /°F)
AAA battery (battery not included)