Which size of collar should I ask?

You already have a collar

Put the collar open, flat on a table.

Measure the distance from the used hole to the point of attachment of the buckle at the colllar (see figure). This is the size you need to search on the site.

Do not add extra distance to the measured distance.

You don’t have a collar

Measure the neck of your dog just below the ears when his head is lifted up.

Do not add extra distance to the measured distance.

Why no extra distance?

We kept that in mind. The extra distance is the distance between "attachment of the buckle" and "closing point of the buckle".

For smaller dogs, this is about 1.5 cm. For the larger dogs approximately 2 cm.