Like many Swiss watchmakers, IWC used movements and ebauches from ETA in their mainstream watch models for decades, from the 1970s through the 2010s. Most are produced to IWC specifications at ETA before being enhanced and decorated by IWC.
IWC began by sourcing the ETA 2892-2, enhancing the finishing and adding modules, in the 1980s and 1990s. When ETA introduced the 2892A2, IWC was quick to adopt it for the 2000s. Once ETA began restricting such sales, IWC switched to Sellita's similar SW 300-1 for the 2010s.
Starting in 2017, IWC began transitioning to movements such as Cal. 32110 and Cal. 82110 which use the same architecture as the 2892 but are made in-house. It is likely that the Cal. 32000 and Cal. 82000 families will completely replace the Cal. 30000 family soon.
Once IWC began sourcing higher-specification movements from ETA, finishing movements in-house, and adding specialty modules they began numbering them as IWC calibres rather than using the base ETA numbering. This family of Cal. 3000 and Cal. 30000 movements use the ETA 2892-2 base.
In 1998, the Cal. 30000 family was updated to use the then-new ETA 2892A2. Interestingly, the updated winding system in this version of the ETA 2892 was developed by Richard Habring who worked previously at IWC. This series uses the Cal. 37000 and Cal. 30000 nomenclature.
As ETA began restricting movement and ebauche shipments in the 2000s, IWC began sourcing from Sellita. Their SW 300-1 is essentially identical to the ETA 2892A2, though there are some differences in construction and specifications. All Sellita-based movements use the Cal. 35000 numbering scheme. The first such movement, Cal. 35110, appeared in 2012.