Three specs, three different jobs
Beat rate describes the pace of the regulating system. Jewels reduce friction at selected points. Power reserve estimates how long a fully wound watch can run. None of the three, by itself, proves that one watch is superior to another.
Beat rate and frequency
Mechanical watches often list vibrations per hour as vph or A/h. A movement at 28,800 vph operates at 4 Hz: the balance completes eight half-oscillations per second. Higher frequency can support finer time division and a visually smoother seconds hand, but it can also affect energy use and engineering demands. Design and regulation matter more than chasing the largest number.
Why movements use jewels
Synthetic ruby bearings are hard, stable, and low-friction. They are placed where rotating pivots and the escapement experience repeated contact. “21 jewels” therefore describes part of the movement’s construction, not a decoration. Extra jewels may support added functions or a particular architecture; a higher count is not an automatic upgrade.
The escapement and shock protection
The escapement releases the mainspring’s energy in controlled steps and keeps the balance oscillating. Shock-protection systems help sensitive balance pivots survive everyday knocks, but no mechanical watch is impact-proof. Remove a watch for activities that create severe repeated shocks unless it is designed and approved for them.
Power reserve
Power reserve is the expected running time from a full wind until the watch stops. A display on the dial may show remaining energy like a fuel gauge. Actual running time can vary with movement condition, winding efficiency, complications, and use. An automatic watch still needs enough wrist motion—or manual winding if permitted—to reach a full reserve.
What matters most
Look for a balanced specification: a proven movement, appropriate reserve, honest accuracy guidance, suitable water resistance, and service support. Finishing can add beauty, but decorative stripes or polished screws do not replace sound engineering and regulation.