That's the copper nickel, Ian. They are all very close in size (mini), but the CuNi looks so small because it's next to the aluminum bronze, which is by far the largest in order to make weight. These are...
Copper with Mokume Gane sight line
Stainless Damascus with Copper sight line
Niobium (can be anodized, so we played with color; I might change colors again at some point)
Brass
Stainless with Mokume Gane insert
Aluminum Bronze
Copper Nickel