KBS Mortar is a dry mortar mix with a controlled swelling effect, which provides a non-shrinking, homogenous and smoke gas-tight re seal for cable penetrations. Most mortars shrink during drying or curing. KBS Mortar expands while it sets (up to 3%), ensuring a tight and crack-free seal. When mixed to pumping consistency, KBS Mortar will not run or sag, allowing easy build-up of material inside a wall opening. For smaller openings, shuttering is only necessary on one side.