window and kitchen sealant strip

almeria1

after using sealant guns for kichen and bathroom jobs over the years I am never fully satisfied with the final results. Has anyone tried the Polycell sealant strip on their kichen/bathroom? Also when we had new DG windows put in a few years ago it looks as though the fitters must have also used a type of sealant strip for the job- cannot seem to find a similar product at the moment as Polycell only sell strip for kitchen/bathroom use. Any idea which of the DIY shops I could get some. Ta