Plant Pro-Tec Deer and Rabbit Repellents protects your plants from deer browsing using a garlic odor that deer can't stand, but is non-offensive to humans. Each clip slides gently onto a plant or fence. When a barrier on the clip is broken by chewing, the clip will release its odor and repel deer, elk, and rabbits for six to eight months. The Plant Pro-Tec clip is perfect for use in trees, vegetable gardens, and flower beds, and will not harm plants, animals, or people. The odorous mixture in the clips is made of food-grade organic material, and its plastic shell is biodegradable. Each pack of deer repellent by Pro-Tec contains 25 clips.