Zema Tick Detach tick collar for dogs kills ticks for 90 days. It contains the active ingredient Amitraz. Amitraz is an effective way to control ticks that may cause Lyme disease. The active ingredient in Tick Detach paralyzes the tick's mouth causing it to detach from your pet and fall off the animal. The advantage is that no part of the tick remains in your pet, thus eliminating the possibility of infection. And because Tick Detach is quick acting it removes ticks before they can transmit potentially deadly Lyme's disease. Fits necks up to 18". Do not use on puppies under 12 weeks old. Do not use on cats. Active Ingredients: Amitraz-N: 9.0% Other Ingredients: 91% Directions for Use: Place the collar around dog's neck and adjust for proper fit. Trim excess length. Made in France.