Chihuahua: crate, bed and harness size
AKC weight: Not exceeding 6 pounds (AKC Chihuahua breed page). The Chihuahua is #24 in AKC's 2025 ranking (AKC).
Crate: 18" crate (18 x 12 x 14 in) (PetMD crate sizing chart (18" and 22" sizes))
Bed: Small rectangle bed (28 x 18 in) (Orvis Dog Product Sizing Guide (Rectangle bed))
Harness: Measure your dog's chest girth, then check the Ruffwear girth chart. No breed standard lists girth.
Photo: Bonnie van den Born, http://www.bonfoto.nl. The original uploader was Cwazi at Dutch Wikipedia., CC BY-SA 3.0, via Wikimedia Commons (cropped).