This HU is old and nowadays inexpensive, but reliable. Gravely roads are no match for this HU.
Given its age, it does lack some of the spiffier features of newer head units. 2 pairs of preouts, front and rear, plus the aux input, are the only ways to expand this system. The lack of internal crossovers means any amplifiers or speakers need to have their own crossovers.
Bright, nice display. Blue, no way to change it. Buttons are blue also.
If you need reliable, the KDC-319 will not fail you!
On volume and distortion, it doesn't start having any problems until 28 out of 35 (on its own volume scale)