This is the Ultra High RPM Fan from Muchmore Racing for Motor and ESC. Used to cool your motor and speed control. FEATURES: Ultra High RPM Micro Black 2-pin Connector INCLUDES: (1) 25x25mm Ultra High RPM Fan REQUIRES: Installation SPECS: Length: 0.985" (25mm) Width: 0.985" (25mm) Thickness: 0.42 (10.7mm) Rated voltage: 5V-9V Maximum airflow: 5.2CFM JML 2.21.12 EEW 5/14/08 ir/jxs