Using measuring tape:

- Length is measured from the front to back of the vest, so along the spine of the animal.

- Width is measured from the left to right of the vest when flat, so from the left-side to right-side of the animal.

- Chest is measured circling all around the torso area.

- Neck is only the strap, measure to where the vest should start on one side until it reaches the opposite side.

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Extra Small (XS)
Length (INCH): 10.5
Chest (INCH): 17 - 22
Neck (INCH): 7 - 12.5
Width (INCH): 10

Small (SM)
Length (INCH): 12.5
Chest (INCH): 19 - 26
Neck (INCH): 8 - 14
Width (INCH): 11.5

Medium (MD)
Length (INCH): 16
Chest (INCH): 23 - 29
Neck (INCH): 9 - 15.5
Width (INCH): 13.5

Large (LG)
Length (INCH): 18
Chest (INCH): 25 - 31
Neck (INCH): 10 - 16.5
Width (INCH): 15

Extra Large (XL)
Length (INCH): 20.5
Chest (INCH): 26 - 33
Neck (INCH): 11 - 18
Width (INCH): 16

Double Extra Large (2XL)
Length (INCH): 22
Chest (INCH): 27 - 34
Neck (INCH): 12 - 20
Width (INCH): 17.5