There are two types of 2-tone kits.

 One is Standard, the other Sport.

Standard 2-tones the seat by simply assembling different leather color parts.
 The insert color runs up the middle vertically.

 For example: Dark-Tan bolsters with Light-Tan inserts as shown here:

 
Sport 2-tones the seat by intentionally cutting perfectly good parts in half,
 to add the insert color onto the bolsters.
 This 2-tones the seat horizontally.

For example: Dark-Gray with Light-Gray inserts as shown here:
 
(Super-Sport style shown here)
Sport, Semi-Sport, & Super-Sport styles available.