Like all T3 Model droids T3-M8 sports a single eye like projector and recorder in the center of a rotating disk atop the typical slanted cylinder of Astromech droids everywhere.  An older model not often seen around the T3's front wheel legs attach at the top of its body, which slopes backwards on it's way down to the third wheel assembly.  The majority of it's probe appendages are mounted on the top disk or extend directly up.

Unlike most droids T3-M8 sports a full body paint job, even stranger than its presence is the depiction, fancy clothes common to what many pre space naval cultures would call the age of sail, with an accompanying 'eye-patch' painted to the left of the droid's single yellow eye complete with skull and crossbones.