The rubbers on a Billiard table are located on the cushions and enable the ball to rebound. There should be very good bounce on a Billiard table and over time these rubbers may deteriorate.
Generally the ball should be able to rebound 4-5+ times. If a tables bounce dies, the rubbers may need replacing. This is generally undertaken off site as it is messy and requires specialised tools.
A good time to check if the rubbers need replacing is when you are re-clothing the table as the cushion cloth has to be taken off and replaced.
The Snooker Kiosk carries a variety of rubbers to suit all types of tables from Australian Redgum to Peridon to Northern Ireland rubber.