Let me start by saying these little blue fobs saved my sanity when my cat lost his PetLibro feeder's original RFID tag. At just $0.35 per tag, this 20-pack is an absolute steal for backup tags.

The plastic casing feels durable enough for daily use, and the included metal keyring makes them easy to attach to collars or keychains. I was pleasantly surprised that they worked perfectly with my pet feeder despite being slightly wider than OEM tags.

Important note: These ONLY work with 125kHz unencrypted systems (like EM4100/4102). They won't function with encrypted systems like HID or Kaba - a limitation clearly stated in the product description that some negative reviewers seem to have missed.

Each fob comes pre-programmed with unique ID numbers, which was crucial for my pet feeder setup. The water-resistant ABS plastic holds up well - my cat's drool hasn't damaged them yet!

While primarily marketed for access control systems, I can personally confirm they work great as affordable replacements for pet feeder RFID tags. Just double-check your device's frequency compatibility before purchasing.

The only minor downside is the slightly bulkier size compared to some OEM tags, but at this price point with reliable performance, it's a compromise I'm happy to make.