DC Series Size AxBxC IP Rating Max Airflow Features SD175SAP (CW/CCW) 172x152x51.6mm / 6.7x2inch IP68 310 CFM Alarm,Tach,PWM, SC, SV 0~10V SD1238PT (CW/CCW) 120x120x38mm / 4.7x1.5inch IP68 146 CFM Alarm,Tach,PWM, SC, SV 0~10V