The main difference between the Marttiini Tundra Knife CB and GR is the color and finish of the handle. The CB version has a natural-colored, waxed curly birch handle, while the GR version has a deadwood-like, gray-waxed curly birch handle. The CB version has a more traditional look, while the GR version has a more rugged and weathered appearance. Other than the difference in the handle color and finish, the knives are identical in terms of their materials, dimensions, and properties.