The internal weight will increase the weight of the keyboard while also slightly modifying the sound profile. Brass and copper will add the most weight.

Black	Anodized aluminum
Multicolor	PVD-coated stainless steel
Brushed Stainless	Brushed stainless steel
Brass wave	Wave pattern CNC'd and clear-coated brass
Copper wave	Wave pattern CNC'd and clear-coated copper