Appearance
A Brittany is typically quite athletic, compact, and solidly built without being heavy. Other characteristics include long legs, and their expressions are usually of intelligence, vigour, and alertness. Their gait is elastic, long, and free.
Some Brittanies are born with naturally short tails and others with long tails. If born with a long tail it is normally docked to a length of 3 to 10 centimetres (1 to 4 inches).
Brittanies come in a variety of colors, where an orange and white coat or liver and white are most common in the American Brittany. Other colors include orange roan and liver roan, all of which are acceptable in the show ring.
The American Brittany Standard does specify an acceptable tri-color of liver, orange, and white with very specific color placement which is also acceptable in the show ring.
Size
Brittanies should range in a height of 17 inches to 20.5 inches at the withers (17.5 to 20.5 in America), with females at the lower end and males taller. A properly constructed and healthy Brittany maintains a weight between 36 and 43 lb (16 to 19 kg), depending upon height. North American field lines tend to be larger, with many dogs reaching a healthy weight of 45 to 50 lb (20 to 23 kg).
Types
Many breeders differentiate between "American" Brittanies and "French" style Brittanies. Although generally recognized as sub-sets of the same breed, there are recognizable differences between the two. The French Brittany appears more "spaniel-like" in that it is smaller and the French Brittany generally works more closely to the guns, but will work according to the local terrain. However, some breeders consider these "differences" to be unsound generalizations.
Source: The American Brittany Club