Cap Feeder Service specification should start with the real closure.
Service needs often show up as jams, inconsistent orientation, worn tracks, sensor faults or operators needing to adjust the machine too often. A clear description of the symptom, photos and cap samples help narrow the cause quickly.
For a better buying decision, the useful comparison is not only hopper size or headline speed. It is how the feeder behaves with your closure, how the capper receives the cap and how easy the line is to run after changeover.
The safest specification route is to start with real closures, target output, line photos and the exact point where the cap must be presented. That avoids choosing a feeder on a generic speed figure that does not match the cap or capper.