Protect your plants from snail and/or slug occupancy with the Slug Shield. This snail and slug deterrent, which is non-toxic and safe to use on plants, works by providing a physical and electrochemical barrier that prevents snails and slugs from climbing up your established plants and trees up to 4" in diameter. How it works: Slug Shields are similar to a miniature electric barbed-wire fence that draws on our planet's natural electric field as its electricity source, creating an electrochemical barrier. The electric charge produced on the copper element wards off snails and slugs. Installation: Wrap the Slug Shield around a plant's stem or base (for best results, wrap around the plant stem two times and do not stretch out tight). As the plant grows, the Slug Shield will stretch accordingly. Make sure there are no gaps that allow the snails or slugs to climb up the plant. To protect larger plants, just attach multiple units together by twisting their ends with one another.