generally only an aesthetic improvement, increases as well with the grade. ETA 2892 The ETA 2892.A2 is a newer design dating to the 1970s and fitted with top quality components. An automatic winding, 21-jewel movement, the 2892 is available in three executions or grades: Elaborated, Top and Chronometer. The key components which differ at the line of demarcation between Elaborated and Top are the balance wheel (Elaborate=Brass/Top=Glucydur) and the hairspring (Elaborate=Nivarox 2/Top=Anachron). In contrast, since the addition of the "-2" at the end of the movement number, there has been no difference between the standard and the chronometer grades in terms of the regulator mechanism, both being Etachron. The degree of decoration on the movement's parts also increases with the grade. To illustrate the differences in accuracy garnered by the successive grades, consider the following specifications: Elaborated grade is adjusted in four positions with an average rate of ±5 seconds/day, with a maximum daily variation of ±20 seconds; Top grade is adjusted in five positions with an average rate of ±4 seconds/day, with a maximum daily variation of ±15 seconds. Chronometer an average rate of −4/+6 with a maximum daily variation of ±5 seconds - standards prescribed by the COSC. The wider range for the chronometer grade is designed to take into account the differences in a watch's rate between static positions, as when the tests are performed, and the dynamic positions as when a watch is actually worn. Chronometer grade movements are serial numbered. The ETA 2892.A2 is usually found in the more expensive and prestigious watches and brands, and owing to its relatively slim height of 3.60 mm, the 2892.A2 is a favorite of watch brands that market complicated movements such as Breitling with its trademark chronograph (stop watches). The 2892 is also used in certain International Watch Company watches, including newer Ingenieur models introduced in 2013. The Omega coaxial based upon an ETA movement Omega's Seamaster line of watches (including the Seamaster Professional 300) previously used an embellished version of the ETA 2892.A2 known as the Omega 1120. Later versions of the Seamaster used a proprietary coaxial escapement invented by George Daniels, an English horologist, and exclusively marketed by Omega, a sister company of ETA. The movement with the coaxial escapement is known as the Omega 2500 series and is derived from the ETA 2892. Later versions of the Seamaster "Planet Ocean" migrated from the Omega 2500