Ball valve with visual stem-cap engagement

A valve comprising:

• a valve body defining a first end, a second end, an interior surface, and an exterior surface, the first end defining a first opening and the second end defining a second opening, the interior surface defining a main bore extending from the first opening to the second opening, the main bore defining a fluid path from the first opening to the second opening, the valve body comprising a stem portion defining a stem bore intersecting the main bore;
• a valve sealing element positioned inside the valve body;
• a stem positioned inside the stem bore of the valve body, the stem comprising a first end and a second end, the first end of the stem engaged with the valve sealing element;
• and
• a cap fixed with respect to the stem and thereby prevented from translational or rotational movement with respect to the stem, the cap comprising a mounting end and an actuating end;
• the mounting end defining a stem engagement cavity;
• the actuating end distal from the mounting end;
• the cap defining a first side surface, a second side surface, and a top surface;
• the cap defining a window in a position between the mounting end and the actuating end;
• the window defined in and extending from one of the first side surface, the second side surface, and the top surface;
• and the window exposing a surface of the stem but preventing passage of the stem through the window.