Picture displayed is a X Small/Small Collar. Also available in large.  
 
Two Sizes:
X Small/ Small 16 - 22 cm.  1 cm width
Medium/Large 25 - 32 cm. 1.5 cm width 
Or please advise neck circumfrence for custom fit.  
 
Small collar has:
- Breakaway Buckle & elastic for quick escape
- Removable Jingle Bell
 
Large Collar has:
- Elastic strap for quick escape
- Removable Jingle Bell