Wholesale Long Life 90 Day Dog Flea Collar BY by Hartz The Hartz Longlife 90 Day Flea Collar for dogs kills fleas and deer ticks which may carry the organism which causes Lyme disease. For dogs whose necks do not exceed 21". Protect your dog during the outdoor seasons. To activate collar, just hold the collar at each end and stretch. One collar lasts for 90 days! Don't take a chance with your pet's safety. Do not use on puppies less than 6 weeks of age. Made in the USA. Each package contains one collar that weighs 0.67 oz. There are 48 collars to a case.