The MCP35X-HS is an optional heatsink compatible with all Swiftech MCP35XX series pumps (MCP350, 355, 35B, 35X). The heatsink is intended to provide additional cooling to pumps running under high stress and/or high ambient temperature conditions. The substantial reduction in operating temperature may result in increased components life. The MCP35X-HS heatsink is designed to operate either in passive mode (without a fan), or can also be fitted with an optional 80x15mm fan. It is bolted to the pump base and mated via a thermal pad. Feet terminated by rubber bushing for noise/vibration insulation are included with the product. When used in passive mode, the heatsink orientation can be rotated 90 Degree in relation to the pump so that the fins will fully benefit from existing air-flow.