The SyncSystem™ Cooling Fan for Racks includes 4-fans as a 1U shelf. The fans can be positioned at the top of your rack or throughout the middle of it to increase airflow throughout the whole rack. Included in the kit are four fans, a 6ft power splitter cable with NEMA plug, and mounting screws. The fans produce only 24.9 dB of sound per fan and have a combined airflow of 100 CFM.