DETHLAC INSECT LACQUER (long term residual effect) 250ml. Kills ants, cockroaches, woodlice and lots of other crawling insects. For both indoor and outdoor use. Dethlac has been eliminating insects effectively since 1959!! DETHLAC may be applied to any firm non-absorbent surface i.e. on doors, window frames (not upvc), skirting boards, shelves, concrete patios etc. DETHLAC dries to hard clear film, which kills insects within a few hours of coming into contact with treated surface. One application remains fully effective for months, even when it rains. You can wash the surface (with or without detergents) and Dethlac will go on killing insects. DETHLAC INSECT LACQUER is not designed as a space spray; it is a surface spray (spot, band, crack and crevice treatment). It should not be sprayed onto wallpaper, fabrics, furniture, glass or matt surfaces.