These cylindrical planters are the same width from top to bottom and have a lovely grey/blue matte finish to them.
 
Dimensions (approx):
Small: external 11.5cm wide, 11.5cm tall. Will take a pot up to 10.5cm diameter.
Medium: external 13.5cm wide, 14cm tall. Will take a pot up to 12cm diameter.
Large: external 16.5cm wide, 16.5cm tall. Will take a pot up to 15cm diameter.