Slip on collar style - designed for collar to fit through the top. The sizes shown below is the width of the fabric, (not the neck size of your pet) the fabric should be measured to go around the front and partially around the sides. 

Please see our size guides in the photos

X-Small 18 - 19cm around neck - collar needs to be no wider than 3cm 

Small:  21 - 22cm around neck - collar needs to be no wider than 4cm 

Medium: 25 - 26cmaround neck - collar needs to be no wider than 4cm 

Large: 30 - 31cm around neck - collar needs to be no wider than 4cm