G4 Pond Sealer is a moisture-cured polyurethane, which forms a non-porous seal on concrete, brick or porous stone. G4 uses the moisture in the air and substrate to cure or harden. It can be applied onto slightly damp substrates. However, it is important that the substrate is sufficiently dry to be porous so as to enable the first coat of G4 to bond and obtain a mechanical grip. G4 can be applied in poor weather conditions, high humidity and at temperatures down to 0°C. G4 seals out lime.

Available in clear, blue, black and green.