I have two chihuahua mixes (9 & 12 lbs). The small size collar is perfect for them. The 3/8 inch width doesn’t overwhelm their necks. I bought a red one for my male dog several years ago and it’s holding up really well. Nevertheless I purchased a second one to have for a backup and also a pink one for my female dog. The design is cute, the latch works well, and the bones are reflective, which comes in handy when I take them out at night. The Red Dingo brand is good quality and I definitely recommend these collars.