Tetrion Smart Filler has developed as a lightweight smart filler with Microlite Technology is the ideal filler for filling large holes or hairline cracks in one easy application. Smart Filler will not shrink, crack or slump and is super smooth with little or no sanding required. Sets 10 times stronger than ordinary lightweight fillers, meaning you can nail or screw straight into the filler with no need for wall plugs or drilling. The fast-drying formula can be over-painted or wallpapered in 15 minutes and is suitable for use on a wide variety of substrates