The block is constructed of high-purity copper that is nickel electroplated to prevent oxidation. A high-flow design is used to allow multiple blocks to run in series. Top and bottom ports can be used to configure parallel or serial designs in multi-block setups.Block Material: Nickel Electroplated High Purity Copper / Acrylic. Backplate Material: Black Anodized Aluminum (not in contact with coolant).