The Hario Polaris scale features a built-in recipe function that accurately calculates the amount of hot water you need to pour for your coffee.
Be more precise; drink better coffee. 

The percentage display allows you to see the percentage of hot water that has been poured relative to the amount of hot water to be poured at a glance. With the Polaris, you don't need to calculate every single pour. If you want to do five pours, simply pour 20% at a time. Or if you want to do four pours, increase your pour to 25%. Simply keep an eye on the percentage display going up to 100%.

Details:

Dimensions: 6.5" x 5.0" x 1.1"
3 AA batteries (included)
Extraction ratio range: 1:1 - 1:30 (0.5 increments)
Weight accuracy:  0.1-300g : 0.1g | 300-1000g : 0.5g | 1000-2000g : 1g

HARIO JAPAN