Evercool EC4020SH12BP 40mm x 20mm Hi-Speed Dual Ball Bearing PWM 4 Pin Fan,x 20mm Hi-Speed Dual Ball Bearing PWM 4 Pin Fan Evercool EC4020SH12BP 40mm, Evercool 40mm x 20mm High Speed PWM Fan mounts on standard 40mm fan holes, This fan uses energy saving PWM, and has a 4-pin PWM connector type,Evercool EC4020SH12BP 40mm x 20mm High Speed PWM cooling Fan.4 Pin Fan Evercool EC4020SH12BP 40mm x 20mm Hi-Speed Dual Ball Bearing PWM.