The following measurements are the dimensions of the actual product, not of the pet they fit. After measuring your pet, make sure all measurements fit within the following dimensions (with a little room to spare in the chest and neck).
| CHEST
(most important) | NECK | WEIGHT |
| X-SMALL | 10 - 13" | 8 - 10" | 3 - 6 lbs. |
| SMALL | 12 - 16" | 11 - 13" | 6 - 10 lbs. |
| MEDIUM | 15 - 19" | 13 - 16" | 11 - 16 lbs. |
| LARGE | 18 - 23" | 17 - 19" | 16 - 25 lbs. |
| X-LARGE | 22 - 27" | 21 - 24" | 25 - 45 lbs. |
