Ala Stop Siligel is a thick liquid (it is not a glue!) that can be applied indoor or outdoor on any hard surface. When birds fly on this gel they are hampered by its thickness and they chose different places for their stationing. Ala stop Siligel is odourless, uncoloured and it can be used on any surface. Particularly effective on gutters, ledges, banisters, balconies, roofs, monuments, etc, this product does not damage the treated surface.