The description of the boot says that it is mated to a 75 mm sole. Where is this measurement being taken? Is there a measurement I should take on my skis / ski binding to ensure that these boots will be compatible? Thanks!

Tech Specs:

Material:

Synthetic cuff 

Binding Type:

75mm 3-Pin binding 

Lacing:

Speed Lacing system 

Recommended Use:

Recreational touring in old-school bindings 

Manufacturer Warranty:

1 Year 

Country of Origin:

Slovenia