From Morrisons
Sink & Drain UnblockerGets to work immediately. Dissolves build up. Powerful cleaning action which powers thorough blockages and clears blocked sinks. Destroys bad odours. Leaves a fresh fragrance after use. For use in sink, shower and bath plugholes. Fast acting thick formula sinks to where the blockages lie. Regular use tops the build up. Safe to use with septic tanks.