The TDS-3 Water Tester is a handheld device that measures the Total Dissolved Solids (TDS) in water, expressed in parts per million (ppm) or milligrams per liter (mg/L). It also measures temperature and has several convenient features such as:
 
 Hold function to save measurements for easy reading and recording
Auto-off function that turns off the instrument after 10 minutes of non-use
Measuring range of 0-9990 ppm with 1 ppm resolution up to 999 ppm and 10 ppm resolution for 1000-9990 ppm
The device is suitable for various applications such as water purification, aquaculture, hydroponics, aquaponics, and wastewater regulation.
 
Some important notes to keep in mind: 
Do not drop the instrument in water or beyond the maximum immersion level as it is not water-tight.
Do not store the instrument in high temperatures or direct sunlight.
The device comes with a pouch with a belt clip, manual, and two 1.5V button cell batteries (LR44).
 
The specifications include:
Accuracy: +/-2%
Working temperature: 0-80°C
UV resistant: No
Maintenance involves replacing the batteries when they are depleted.
 
Dimensions:
15.4cm x 2.9cm x 1.9cm and weighs 72g.
Shipping dimensions are 15.7cm x 3.1cm x 2.5cm and weighs 100g.