How  Canadian 4 digit jacket sizing works
 
*The first two digits indicate the approximate height of person in inches.
And the last two digits indicate the chest size in inches.
Example size 7044
This jacket is best suited for someone 70 inches tall with a 44 inch chest.

 Canadian Alpha sizing

Chest sizes

Small        33"to 37"

Medium    37"to 41"

Large        41" to 45"

Body length

Short         63"to 67"

Regular     67"to 71"

Long(Tall)  71"to 75"

CANADIAN GORE-TEX