With parked created rEad the offers the comforts power threshold buy for your dog's size. Small size: For dogs with a neck width up to 14″ Large size: For dogs with a neck up to 22″ Active ingredient: Deltramethrin Deltramethrin is a type of pyrethroid insecticide. Pyrethroids are considered safe for dogs, but are dangerous for cats any pyrethroid based dog flea product, like this Adams collar, should be kept well away from cats. Despite the fact that this sort of chemical is considered safe for use on dogs, some dogs are sensitive and experience negative side effects such as mild to severe skin reactions. If this happens with your dog, remove the collar right away. Unfortunately, the Salvo collar presently has too reports of concerning side effects for us to be able to confidently recommend it as a quality and safe flea control option. Issues that I've come across include a burning sensation on the neck, and severe inflammation on the neck. Concerningly, some dog owners have also noticed their dog having muscular spasms as a more severe side effect of using the Salvo dog collar for flea control. This collar is another option for people looking for a non-chemical based solution for flea and tick control. The Dr Mercola herbal collar is a repellent that means it aims to stop insects, including fleas and ticks, from being attracted to your dog's body. The formula relies on natural plant based oils: Geraniol, Wintergreen and Almond oil. The collar slowly releases a small amount of oil out over time, it's constantly working to ensure the ingredients are being diffused on to the dog. The almond oil portion of the formula also acts as a skin conditioner. But it's geraniol, the main active ingredient, which does most of the work repelling fleas the Dr Mercola Herbal collar. Geraniol is a plant oil that is extracted from several plants, including geraniums and lemongrass. Geraniol was found out only 1999, after extensive scientific testing, that this ingredient is excellent natural insect repellent. The collar is rated to be able to repel fleas and other insects for up to 4 months maximum, as well as being waterproof. However, the exact amount of time it's effective also depend on environmental conditions and other factors; not everyone is seeing 4 months of protection with this collar, and some do need to replace it sooner than that. The Dr Mercola herbal brand also has a topical spot-on solution which is safe to use alongside this collar for extra strength. This collar is currently a new kid on the block. It's given the name ProGuard+, which you may have seen on other flea products the past. But this collar is made and sold by a new company called Grand Pets. Marketed on the fact that the Grand Pets ProGuard+ collar uses the same formula as the national leading brand, but with a lower price tag. This collar does indeed use the same active ingredients as you'll find the Seresto collar. These are: Somewhat misleading is the fact that the company states that the collar uses natural ingredients which technically isn't true, as it uses the same insecticide ingredients as some other flea products. While these are often initially derived from natural sources, they are chemically synthesized and are not natural the sense that true herbal extracts are, for example. does that mean that this collar is exactly the same as the Seresto? Yes and no. While the active ingredients are indeed the same, at the same percentages, both brands have 85% of their formulas listed as other ingredients. Both brands do not disclose what these other ingredients are Essentially that