Dial from which the time can be read at night and without additional illumination. To do this, the numerals or hour markers and hands are filled with a luminous material. Only seven years after, when radium was discovered by Marie and Pierre Curie in 1898, the quinine factory Büchler & Co. in Braunschweig, Germany, began marketing luminous dials and watch hands. Pure radium is highly radioactive, so this element is no longer used on luminous dials. Tritium, a radioactive isotope of hydrogen with an atomic weight of 3, also became obsolete. Watches with tritium as the luminous material can be recognized by the words "Swiss Made - T" on the dial. Instead of these radioactive substances, modern luminous dials are based on alternative substances that are not radioactive but still luminous, for example Super-LumiNova.

A system to protect the fine and therefore very delicate pins of the balance staff from breaking. To do this, the jewellery and terminal stones in the balance staff's bearing are resiliently secured to the scale plate and spigot. When the watch is hit by a strong blow, these jewels collapse laterally and/or axially. A shock-absorbing watch should be able to survive a fall from a height of one metre onto a wooden floor undamaged. After the drop, the speed of the watch should not show any major deviations. Watches with shock-absorption systems were first marketed in the 1930s. Shock absorption had become standard equipment by the 1950s. Originally, many watch brands used their own shock-absorption systems (partly to reduce costs), but these systems did not survive in the long term. The best known and most widespread shock-absorption systems are the so-called 'Kif and Incabloc' systems. The latter can be recognised by its stabilising spring, which is shaped like a lyre.

Incabloc, one of the most common and widely used shock- absorption systems for mechanical watches, was first mass-produced in 1933. It is generally recognised as the most successful shock-absorption system in the history of portable watches. Its success is partly due to the fact that this shock-absorption system can be easily integrated into all calibres. The Incabloc shock-absorption system is usually shaped like a lyre.

Developed by Portescap, this adjustment system for mechanical watches does not require the typical index. The outer end of the balance spring is squeezed between two elastic rollers. The position of one of these rollers can be shifted with the help of a star-shaped component, thus lengthening or shortening the balance spring and altering the speed of the watch. This operation would otherwise be performed by the indexing system, which is rendered unnecessary by the Incastar solution.

The text of a patent granted to a movement with a jump-type seconds hand describes the independent seconds mechanism as "a mechanism for the gradual forward movement of the seconds hand on a gear-driven watch movement." In essence, this is nothing more than an ordinary mechanical caliber. On a watch whose balance wheel has a frequency of 18,000 beats per hour, the independent seconds mechanism counts five vibrations, then releases the seconds hand, which (as on a quartz watch) jumps forward in a full-second increment.

In clock movements with indirect central seconds, the pulse of the second hand comes from outside the flow of energy passing through the gear train. For this reason, this type of seconds mechanism is frequently found on gauges that were originally built to support small seconds counters and later rebuilt to support an "sweep". Modern gauges are generally built to support a centrally axial " sweep". For this reason, they usually have direct central seconds, that is to say, the pulse for the second hand is within the flow of energy passing through the gear train.

An additional protective cover (dome or cuvette) under the outer back cover of a watch. This type of additional cover is most commonly found on pocket watches. Early wristwatches with hinged cases sometimes also had inner covers.