CPL DuraShield L LithiumConpell Dura Shield L lithium densifier. High performance, water based lithium silicate surface hardener and densifier. Reacts with the calcium hydroxide within the concrete matrix to grow its own interlaced crystal structure, hardening the concrete surface and reducing pore size. Penetrates more effectively than sodium or potassium silicates. Intended for use on Steel trowel finished concrete or mechanically polished floors after the grouting stage.