DUO Technical Gear
Sizing & Fit Guides
Find your size, then choose your harness model.
Measure your dog
Two measurements: base of neck + torso. These two numbers determine your size across all DUO harness models.
Base of neck
Measure the circumference of the base of your dog's neck, where the neck meets the chest. Not the collar line — lower, at the shoulders.
Torso
Measure the circumference of your dog's torso around the largest section, usually just behind the armpits.
How to measure your dog for the perfect fit
Size in real life
One dog per size. All wearing DUO.
| Size | Torso | Neck | Dog weight | Webbing | Typical breeds |
|---|---|---|---|---|---|
| XS | 15"–19" | 9"–12" | 8–18 lbs | 3/4" | Chihuahua, Toy/Mini Poodle, Yorkie, Papillon, Pomeranian, Mini Dachshund, Italian Greyhound, Maltese |
| SM | 20"–25" | 13"–17" | 19–35 lbs | 3/4" | French Bulldog, Pug, Boston Terrier, Jack Russell, Mini Schnauzer, Cavalier, Cocker Spaniel, Beagle, Dachshund, Corgi |
| MED | 26"–28" | 18"–21" | 36–50 lbs | 3/4" | Border Collie, Australian Shepherd, Springer Spaniel, Whippet, British Bulldog, Basset Hound, Standard Poodle (female) |
| LARGE | 29"–32" | 22"–25" | 51–79 lbs | 1" | Labrador, Golden Retriever, German Shepherd, Belgian Malinois, Boxer, Doberman, Pit Bull (most), Siberian Husky, Weimaraner |
| XL | 33"–35" | 25"–27" | 80–100 lbs | 1" | Rottweiler, Bullmastiff, larger German Shepherd, Bernese Mountain Dog, larger Golden and Labrador males, Rhodesian Ridgeback, Anatolian Shepherd, Presa Canario |
| XXL | 36"+ | 26"+ | 100+ lbs | 1.5" | Great Dane, Saint Bernard, English Mastiff, Newfoundland, Great Pyrenees, Irish Wolfhound, Cane Corso, Leonberger, Bullmastiff (large males) |
Harnesses have a lot of room for adjustment. If your dog falls between two sizes, use weight to decide.
Dogs over 100 lbs need the PRO line. PRO sizes start at SM — for dogs under about 20 lbs, choose ESSENTIALS XS.
Long-bodied and narrow-headed dogs — Greyhounds, Whippets, Italian Greyhounds — often size up from their weight. Measure the torso and use that number.
Choose your harness model
Each model has a dedicated sizing, fit & adjustment guide. Pick your harness.
XS
15 lbs
Cute Mutt
SM
35 lbs
Formosan Mountain Dog
MED
48 lbs
Small Golden Retriever
LARGE
65 lbs
Malanois
XL
100 lbs
Newfie
XXL
135 lbs
Cane Corso
Choose your harness model
Three mechanisms, three different problems. Each model has a dedicated sizing, fit and adjustment guide.
DUO Direct
No-Pull Harness
For dogs that pull. The front-clip cinch mechanism reduces pulling without pressure on the throat.
Sizing & fit guide
DUO Adapt
No-Escape Harness
For dogs that escape. The cinch closes escape gaps as the dog backs out or reverses.
Sizing & fit guide
DUO Eclipse PRO
Adventure & Car Harness
For walks, hikes, and vehicle travel. Connects to standard seat belt adapters via the back D-ring.
Sizing & fit guide
