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Part Number Concept & Identification
Most fractional and metric T-slot profiles have part numbers that directly coincide with the profile's physical measurements. Fractional profile part numbers contain four characters. Metric profile part numbers contain six characters, which relate to the profile's series and dimensions. This series part-numbering concept is explained in more detail below.
Fractional Profile Naming Standards

Example: 15 series profiles always measure .75" from the outside edge of the profile to the center of the T-slot.
Metric Profile Naming Standards

Example: 40 series profiles always measure 20.00mm from the outside edge of the profile to the center of the T-slot.