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Production lead time 1-2 weeks Free US Shipping Over $85

Zoom black biothane collar with brass hardward to fit the Fi Series 3
Zoom black biothane collar with brass hardward to fit the Fi Series 3
Zoom green and blue biothane collar with brass hardware to use for the Fi Series 3
Zoom graphics showing available biothane color choices
Zoom graphic showing the options of the Fi Series 3 Biothane Collar Styles

Fi Series 3 BioThane Collar - Brass Integrated Design


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Adventure with total peace of mind with our waterproof, stink proof, easy to clean BioThane collars, compatible with Fi’s newest Series 3 tracking units (sold separately)! The Fi Series 3 unit features an extra long battery life in a sleek, minimalist design. Fi’s proprietary technology uses GPS and satellite data to provide accurate real time data, as well as fitness and sleep data! 

Our Fi Series 3 Compatible BioThane Collars are available in Sport and Classic Brass styles, Layered or Integrated designs, ¾” or 1” widths, and in 16+ colors, allowing you to easily find a collar that matches your dog's personality and style! Please note: these collars are not compatible with the Series 1 or Series 2 trackers. Collars do not include the Fi unit. The unit must be purchased separately at Use code HIGHTAILHIKES20 for $20 off your Fi collar activation fee. 

With our Brass Integrated Design, the Fi unit is built into the body of the collar, making it a little more streamlined than our layered design. Our Brass Integrated Design allows for you to choose a single color or a Two Tone design, with alternating colors for the accents and band pieces (+$8). See photos for examples. All collar styles have been tested for strength and durability. All Series 3 units can be charged without removing the unit from the collar. 

Choose your collar size, and preferred colors for the main band pieces and/or Two Tone pieces from the color options shown. For the single color design, select an strap keeper if desired ($2). The Two Tone design includes a strap keeper as part of the design. A strap keeper is a loop of biothane between the buckle and D Ring that helps keep the tongue of the collar in place. 

Important: please size your dog properly for their collar before placing an order. There are two ways to size your dog for a collar:

  1. Use one of your dog’s existing collars to determine their measurement. Lay the collar down flat on a tape measure or cutting mat and measure the distance from where the two points of the collar meet when the collar is being worn. 

  2. Use a length of string or a soft cable (like a phone charging cable) to measure around your dog’s neck. Allow enough space for 2 fingers (1 inch) to fit underneath the collar to ensure that the collar will not be too tight. Transfer the string or cable to a cutting mat or tape measure and check the measurement. Measure several times to ensure accuracy.

Please also watch this video where we show how to size your dog for a collar.

Your dog’s neck measurement should ideally fit in the middle of the sizing range of the collar that you choose. Due to the Fi Unit and hardware being built into the collar, Fi collar sizing may be different from our standard collar sizing. Please read the sizing options carefully. If you are between sizes, or not sure what to choose, please contact us. We are always happy to help, or to make your collar in a custom size by request. 

All of our BioThane Collars are waterproof, stink proof and easy to clean! Brass is rust proof, but can develop a patina over time. See our blog post about cleaning your BioThane gear. We do recommend rinsing your gear with fresh water and towel drying after a hike or a trip to the beach. This will help to remove salt, sand, and other grit to help your gear last longer. 

Although our products are guaranteed for life, you are responsible for ensuring the safety of your dog. Please inspect your gear and hardware regularly. Never leave your dog unattended in a crate while wearing a collar. 

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Fi Series 3 BioThane Collar - Brass Integrated Design


Customer Reviews

Based on 3 reviews
Lindsey M. (Tucson, US)
Perfect for little thick necks

Mochi’s collar is a way better fit than the one that comes with the Fi tracker. The Fi collar was way too thick and bulky for her tiny length of neck. She needed a size medium because of how thick her neck is but a thinner and slimed collar. This was perfect. Thank you for making such a great product.

Wonderful! We are happy to hear your new HTH Gear is working so perfectly for you (and Mochi!) Thank you Lindsey!

Avery Burke (Birmingham, US)

Collar is perfect except it’s a small. When you place your order beware that if you change the colors, it goes automatically to the size SMALL collar. I accidentally ordered the small meaning to order a large because I changed the color from black to purple. I emailed them and all they could offer me was 15% off another $50 collar. I said absolutely not and will not order from them again.

Hello Avery! Thank you so much for leaving a review! I just wanted to address your concerns as I totally hear your frustrations! First, when you select a size, the size that you select will remain selected regardless of changing the color option or any other options. We'll take a careful look at our product page to see how we can make it more intuitive. Second, I'm so sorry if there was a misunderstanding regarding our return policy! We do ask for a 15% restocking fee on our custom BioThane items, due to the fact that each item is custom made to order by hand. Many makers do not offer returns on handmade items, but we understand that occasionally a mistake is made or the item does not work out! We always strive to work with our customers so that everyone is happy, so please do reach out to us again at and we'll see what we can do to help!

Kimberly C.
Kim C

Ordered one if these for my tiny dog. Very well made, and fits perfectly. Bonus points the color is perfect.

Thank you Kimberly! So glad you're happy with your new gear!