The VJ-4 3.9mm DC from ViewTech Borescopes is a Borescope with Depth of Field(DOF) 8 to 100 mm (front), 5 to 50 mm (side), Viewing Angle 110 Degree, Operating Temperature -20 to 50 Degree C, Storage Temperature -20 to 70 Degree C, Probe / Insertion Tube Diameter 3.9 mm. More details for VJ-4 3.9mm DC can be seen below.