The single most useful thing about this jumper is that the maker published real numbers against every size, which most festive pet knitwear does not. Back length runs from 21cm at S up to 40cm at 2XL, and chest from 28cm to 48cm, so you can take a tape measure to your dog on the kitchen floor and know before you order rather than finding out on Christmas Eve.

It is a polyester knit rather than wool, and that changes how you should treat it. Polyester does not shrink or felt in the wash, dries quickly, and holds a printed snowflake pattern without going bobbly after three wears. What it does not do is breathe the way wool does, so it suits cool rooms and short winter walks better than a dog who is already warm and working hard.

• S: back 21cm, chest 28cm, collar 22cm
• M: back 24cm, chest 30cm, collar 26cm
• L: back 28cm, chest 36cm, collar 30cm
• XL: back 34cm, chest 42cm, collar 34cm
• 2XL: back 40cm, chest 48cm, collar 37cm
• Polyester knit, machine washable at low temperature

Check the measurement first. Back length is taken from the base of the collar to the base of the tail, and chest girth around the widest part of the ribcage just behind the front legs. Weight is not a guide — two 8kg dogs can be two sizes apart. If your dog falls between sizes, take the larger one.

Who it's for: Owners of small and medium dogs who have been caught out by unlabelled pet knitwear before and would rather order once and be done.