Shock protection systems are not all the same, and confusing them is a mistake I still see people make often. There are at least three distinct levels: protection of the balance pivot, suspension of the entire movement within the case, and mechanical distribution of shock waves through the case geometry itself. A watch can have all three, or just one.
The most elementary level is balance pivot protection. Incabloc, the Swiss system patented in the mid-20th century, is the classic example: it allows the balance to shift laterally under impact, then returns it to position. It was fundamental on railroad watches, where vibrations were continuous and the pivot was the most frequent point of failure. KIF is the competing variant, found in many ETA ebauche movements and derivatives; certain manufacturers claim resistance up to 5000 G on reinforced versions.
The next level is movement suspension within the case. IWC spent eight years developing the SPRIN-g PROTECT system, which uses a cantilever spring made of bulk metallic glass — an amorphous material more elastic than any conventional crystalline metal — to keep the movement detached from the case and distribute impact forces across its entire length. It debuted in 2021. Formex works on a similar principle with its patented Case Suspension System: the case floats on a spring structure, and absorption occurs before the shock reaches the movement. MB&F calls its system FlexRing, integrated into the LM101 EVO case precisely to make a watch with a suspended balance wearable on a daily basis.
The third level concerns case geometry. Certina's DS system, born in 1959, features a threaded ring that constrains the movement, a thin metal sheet between movement and dial, and a slightly domed crystal: together they distribute shock waves more uniformly. Recent versions of the DS Action Diver add a contoured ring around the movement. The same physical principle explains why Urwerk mounts miniaturized air turbines visible from the caseback: they slow the escape wheel during winding and absorb impulsive impacts on the gear train.
One fact many overlook: high-beat movements at 36,000 bph recover more quickly from a shock than those at 28,800, because each oscillation cycle is shorter and the accumulated error before return to equilibrium is smaller. It's not a shock protection system, but it is a real chronometric advantage under intensive use conditions. The MIL-STD-810 standard, with 26 drops from 1.22 meters onto concrete on every face, edge and corner, remains the most severe benchmark for those wanting to certify performance numbers in the field.