Why 21–28cm Is a Small-Breed Range, Not a One-Size Fit
A 21–28cm neck range covers many toy and miniature breeds, but it still requires a precise measurement. Too loose and the collar can slip; too tight and it can rub. The collars in this range are 15 mm wide and 2.5 mm thick, made from Biothane—a PVC/TPU-coated material that is waterproof and mould-resistant. That slim width suits delicate necks, but only if you choose the correct neck size from the available options.
This guide walks you through measuring, choosing a size, and accounting for puppy growth, using the Olive, Red, and Amethyst small breed waterproof collars as examples.
How to Measure Your Small Dog's Neck
Use a soft tape measure or a piece of string you can lay against a ruler. Measure the widest part of the neck, usually just behind the ears and above the shoulders, where the collar will naturally sit.
- Step 1: Measure snugly, not tightly: Wrap the tape around the neck so it sits close to the fur but does not compress the skin. Record the measurement in centimetres.
- Step 2: Add a little room: The collar should be snug enough to stay on but loose enough to slide two fingers underneath. The 21–28cm range gives you options, but the product pages list specific neck sizes (e.g., 21cm, 22cm, 23cm), so pick the size closest to your measurement.
- Step 3: Check the fit on your dog: Once the collar arrives, fasten it and check that you can still fit two fingers between the collar and your dog's neck. If it feels too tight or too loose, exchange for a different size before use.
Puppy Growth: When to Size Up
Puppies grow quickly, so a collar that fits today may not fit in a few weeks. The 21–28cm range is designed for small breeds, but if your puppy is still growing, consider starting at the lower end of the range and checking the fit regularly. There is no universal rule for how often to re-measure, but a monthly check is a sensible habit. If the collar starts to feel tight or leaves marks, move up to the next size.
Olive, Red, or Amethyst: Same Fit, Different Look
- Olive Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck: Olive Small Breed Waterproof Biothane Dog Collar: 15 mm wide, 2.5 mm thick, neck sizes 21–28 cm, Biothane material, hardware in Brass, Silver, Rose Gold, or Antique Brass. A neutral, earthy colour that suits everyday wear; the slim 15 mm width is designed for toy and small breeds.
Olive Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck - Red Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck: Red Small Breed Waterproof Biothane Dog Collar: 15 mm wide, 2.5 mm thick, neck sizes 21–28 cm, Biothane material, hardware in Brass, Silver, Rose Gold, or Antique Brass. A bold, classic red that stands out on walks; same fit and material as the Olive version.
Red Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck - Amethyst Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck: Amethyst Small Breed Waterproof Biothane Dog Collar: 15 mm wide, 2.5 mm thick, neck sizes 21–28 cm, Biothane material, hardware in Brass, Silver, Rose Gold, or Antique Brass. A stylish purple option for small dogs with big personalities; identical dimensions to the other colours.
Hardware and Personalisation: What to Know Before You Buy
All three collars offer the same hardware colours: Brass, Silver, Rose Gold, and Antique Brass. Choose one that matches your dog's other accessories or your own preference. Each collar also includes free personalised engraving directly onto the Alumax clasp, so you can add your dog's name or your phone number without a dangling tag. That keeps the collar quiet and reduces the chance of snagging on fur or branches.
Waterproof Care: What the Product Record Supports
The Biothane material is described as 100% waterproof, mould- and bacteria-resistant, and wipes clean in seconds. No specific cleaning instructions (such as soap type or drying method) are provided in the supplied information, so stick to a simple wipe with a damp cloth and avoid harsh chemicals unless advised otherwise.
- Daily wipe-down: A quick wipe after muddy walks keeps the collar looking fresh and maintains the material's resistance.
- Avoid abrasive cleaners: Since the material is coated, abrasive cleaners could damage the surface. A damp cloth is sufficient for routine cleaning.
When to Choose a Different Size or Style
If your dog's neck measures below 21cm or above 28cm, these collars may not be the right fit. The product record does not list sizes outside this range for these specific models, so check the store for other options. Also, if your dog pulls strongly, a 15 mm collar may not be the most suitable for lead training—consider a wider collar or a harness, though the supplied information does not make a recommendation either way.
