1. DOG JUMPERS should be chosen according to the CHEST MEASURMENT. The "Back Length" is a secondary guide for dogs with short (pug) or long (dachshund) back lengths.

2. DOG COATS should be chosen according to the BACK LENGTH MEASUREMENT. 

Chart below shows:
Back length - orange (Base of neck to end of body at tail)
Around chest - yellow (Around the largest part of the chest usually about 5cm behind the front legs)
Around waist - lilac (Around the body halfway along the back length measurement)
Around low neck - green (Around low necklind. NOTE: This is NOT the same as the collar which sits higher)