If the water you will use in your espresso machine is hard, this water softener is a must for your limescale prevention program. Simple instructions prepared by 1st-line on how-to recharge this water softener should be reviewed before installation.
On the Rancilio Silvia espresso machine, the water softener should be attached to the longer hose. This water softener/filter can also be used on the Rancilio S24 espresso machine with a water tank. On both models, you may see a groove on one corner where the filter can attach (unless the Rancilio water tank was redesigned)