From the Spinneybeck website:
This two toned leather is clearly in a class by itself. Hand Tipped is crafted from a premium selection of full grain raw material. The pebble grain character is the result of a specific retannage formulation and extended milling process.
The two toned effect is achieved through the base dye coloration and surface treatment. The tip of the pebble grain is dyed with a dark overtone which is administered by hand. The surface of the leather is further enhanced with a light clear coat application followed with a specialized ironing process.