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Description
K9 Advantix II Flea, Tick & Mosquito Treatment & Prevention for Medium DogsK9 Advantix II Medium Dog is the veterinarian recommended formula that helps defend your dog against five pests: fleas, ticks, mosquitoes, biting flies and lice. And unlike other treatments, K9 Advantix II kills and repels fleas, ticks and mosquitoes. K9 Advantix II topical treatment gets straight to work killing fleas on dogs within 12 hours of initial application. This formula stops existing flea infestations and prevents new ones by killing adult
K9 Advantix II Medium Dog is the veterinarian-recommended formula that helps defend your dog against five pests: fleas, ticks, mosquitoes, biting flies and lice. And unlike other treatments, K9 Advantix II kills and repels fleas, ticks and mosquitoes. K9 Advantix II topical treatment gets straight to work killing fleas on dogs within 12 hours of initial application. This formula stops existing flea infestations and prevents new ones by killing adult fleas on contact so they can’t lay eggs and they don’t have to bite your dog to die. Fleas, ticks, mosquitoes and other pests not only cause discomfort; they may also transmit disease. Monthly use of K9 Advantix II is important to protect your dog against fleas that may cause transmission of tapeworms. This formula also kills fleas which may cause Flea Allergy Dermatitis and flea bite anemia. That’s why K9 Advantix II Medium Dog topical, spot-on formula makes application simple - going on in seconds. It's easier than a flea collar and there are no hard-to-swallow pills. You’ll also love that K9 Advantix II is fragrance-free and waterproof after 24 hours of application. Check the product label for information on application and potential side effects. K9 Advantix II pest protection is effective on both indoor and outdoor dogs. Your dog should be at least 7 weeks old and weigh 11-20 lbs. to use K9 Advantix II Medium Dog. For the ultimate convenience in care, K9 Advantix II is available over the counter – no prescription needed. And, you can stock up with 2-dose, 4-dose and 6-dose packs so you never miss a monthly treatment. Once K9 Advantix II is applied, your dog is ready to get right back to big-pup cuddles and racing around the park. K9 Advantix II Medium Dog is a trademark of Elanco or its affiliates.
Key Features
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K9 Advantix II Medium Dog 30-day treatment & prevention protects dogs 11-20 lbs. from fleas, ticks, mosquitoes, biting flies and lice
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Kills fleas within 12 hours of application
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Vet-recommended formula kills & repels on contact so fleas don’t have to bite your dog to die
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Easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours
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No prescription needed
Directions for Use
Use only on dogs. DO NOT USE ON CATS or other animals. Do not apply to dogs weighing less than 4 lbs. Remove applicator tube from the package. Use scissors and peel down foil. Hold applicator tube in an upright position. Pull cap off tube. Turn cap around and place other end of cap back on tube. Twist cap to break seal, then remove cap from tube. The dog should be standing for easy application. Evenly apply entire contents of the tube along the top of the dog's back, from the shoulder down to the base of the tail. The number of spots depends on the size and weight of your dog (please refer to the product label). At each spot, part the hair until skin is visible. Place the tip of the tube on the skin and gently squeeze to expel a portion of the solution on the skin. Do not apply an excessive amount of solution at any one spot that could cause some of the solution to run off the side of the dog. Do not get this product in your dog’s eyes, or allow your dog to ingest this product.
Storage Instructions
Store in a cool, dry place inaccessible to children and pets. Protect from freezing.
Active Ingredients
Imidacloprid, Permethrin, Pyriproxyfen
Product Form
- Topical
Pet Size
- Medium
Pet Lifestage
- 7 weeks and older
Pet Weight
11-20 lbs
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.5 ★★★★★
Based on 17 reviews
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Product Reviews
★★★★★ 5
Flat tire… try this.
Size: 1 Gallon + Tool, Set name: Small Tire/Bicycle Formula
For husband, that’s what he puts in our tires great price and works well
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Reviewed in the United States on May 26, 2026
★★★★★ 5
Go Ridding and Go Flatless with QuickStrike tire sealent
Size: 1 Gallon + Tool, Set name: Off-Road Formula
I’ve tried several tire sealants over the years on my ebikes and scooters, but FlatOut QuickStrike is by far the best I’ve used. From the moment I added it to my bike tires, I noticed a difference—it’s incredibly easy to install, and you don’t have to convert to tubeless to benefit from its protection. The formula is thin and spreads quickly, sealing punctures almost instantly so you don’t lose much air.
What I feel that really stands out is how effective it is. I ride my ebikes through rough terrain with lots of thorns and debris, and since using FlatOut QuickStrike, I haven’t had a single flat ( unlike before ). Even when I’ve picked up multiple punctures, the sealant has handled them all without a problem. I feel that the peace of mind it gives me is priceless, especially on long rides or commutes where a flat could ruin your day ( and It has in the past ).
Another big plus is that it’s a one-time application—it won’t dry out or turn into a mess inside your tire ( like that Green Stuff ). It’s also safe for both tubes and tubeless setups, and works well in my 20 inch and 14 inch tires. I’ve used it on my ebikes and scooters and the results have been consistently impressive.
Make me feel confident of the durability of my tires on my ride. I bought the gallon bottle because I have a few ebikes and scooters. this stuff works great!
If you want to spend less time fixing flats and more time enjoying your ride, this is the sealant to get. Highly recommend!
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Reviewed in the United States on June 14, 2025
★★★★★ 5
Fat tire savior
Size: 1 Gallon + Tool, Set name: Off-Road Formula
The best fat tire and dirtbike sealant we have found and love the gallon size. Pump clogs but clears with a strong push and love that it is water cleanup.
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Reviewed in the United States on April 16, 2026
★★★★★ 5
Worked perfectly for me. Sorry I waited so long.
Size: 1 Gallon + Tool, Set name: Off-Road Formula
I was clearing a field full of mesquite trees, and my tractor tires were getting destroyed. Mesquite has nasty 3-inch thorns, and I was plugging tires constantly. Eventually, all four tires were flat at the start of each day. These tires had been plugged more than 10 times each.
I bought FlatOut Quick Strike and followed the instructions exactly. The pump dispenses about 1 oz per pump, so I put 30 pumps in each tire, and the bottle was mostly empty by the time I finished. Typical with any pump dispenser it was also difficult to get the last bit out of the bottle using the pump.
It’s been a week now. One tire has lost about 1 PSI, but the other three are still holding exactly where I set them.
Considering how badly these tires were damaged, I’m impressed so far. This is the first time I’ve gone more than a day without dealing with flats in that field.
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Reviewed in the United States on February 13, 2026
★★★★★ 4
Pump is worthless
Size: 1 Gallon + Tool, Set name: Small Tire/Bicycle Formula
The sealant is good. The gallon pump is a joke. Pump stopped working 4 pumps in. Went and got another replacement pump from automotive store, also broke after 4 pumps. Ended up cleaning out an old Slime bottle and pouring in the flat out sealant in the slime bottle, so I could actually get it in my tires.
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Reviewed in the United States on May 30, 2026