The 3976832 Belt Tensioner ensures optimal performance for Dodge Cummins 4B3.9, 6B5.9, C8.3, ISB, QSB engines. Compatible with part numbers 3911621, 3922901, 3928748, 3934823, 3934824, 3936207, 3936208, 3937556, and 3973825. Reliable and durable for heavy-duty applications.