Note: There may be slight errors of 2-5cm in manual measurement S: Inner diameter 25cm  S: Outer diameter approximately 45cm
M: Inner diameter 30cm  M: Outer diameter approximately 55cm
L: Inner diameter 40cm  L: Outer diameter approximately 70cm
XL: Inner diameter 50cm  XL: Outer diameter approximately 85cm

Size reference:
model
Tile size and groove size are applicable
Small size S (1) within 2 pounds, around 40cm-50cm, 30cm, milk dog, milk cat
rice
Medium size 50cm -60cm 4 10cm or so Puppy kittens weighing less than 6 pounds
Large size 60cm-75cm60cm, small dogs and cats weighing less than 15 pounds
Increase by about 80cm to 90cm and 70cm for small and medium-sized dogs and cats, weighing less than 30kg