This is one of those products you need but are not quite sure. I bought this with an open mind to do quite a big job, where I had taken and edge off a cupboard, sawn it down and re-stuck the edge back on. The saw edge was rough but this filled and smoothed well. The lumps came and were quite hard so I couldn't see how this could possibly work. However, I tried and actually as I rub the block along the target area the end becomes malleable and it does a really good job. Due to the size of the of he holes I had to build it up but found it was easy to do for a few minutes each day and now nobody would know.