This is an exact replacement cooling fan for a vast number of HP-Agilent and Tektronix machines.
Comair Rotron Model MX2B3 Muffin-XL
Do a google search,these are some of the most expensive fans out there.
Mounting screw holes are 4 1/8 inches apart.
Unit measures 4 3/4 inches square by 1 1/2 inches deep.