Enables an easier view of the water level when filling up the flask.
This fits the upper rim of the Pinter beer flask which may be found here thegreatergood.co.uk
When filling the Pinter with water, use this indicator to easily see the water levels.
Press the hooked end of the indicator down over the rim of the Pinter with the platform down inside the flask. Lower the indicator until it beds down on the flask rim.
The correct amount of water is shown when the water reaches the level of the little platform.