The Patek Philippe reference 3700 is recognized as the original Nautilus model. It established the distinctive porthole-inspired case design and integrated bracelet that define the collection. This reference was produced for a significant period, laying the foundation for subsequent Nautilus iterations and solidifying its place in the brand's sports watch offerings.

This reference features a stainless steel case measuring 42 mm in diameter and 7.6 mm in thickness, fitted with a sapphire crystal. It houses the self-winding Caliber 28-20 C, which provides a power reserve of 45 hours. The watch is water-resistant to 120 meters and typically presents with a blue dial, offering a date complication.

The 3700 appeals to collectors interested in the foundational pieces of significant watch lines. It represents the initial vision for the Nautilus, preceding later mid-size and complicated versions. Its production run from 1976 to 1990 saw various dial and bracelet configurations, making specific examples of interest to those studying the model's evolution.

The Patek Philippe Complications Reference 5712 is a notable offering within the brand's Complications collection, distinguished by its asymmetrical dial layout and a suite of practical indications. It presents a sophisticated blend of functionality and design, offering a moon phase, power reserve indicator, and an analog date display, all arranged to create a distinctive visual identity that sets it apart from more traditional Patek Philippe designs.

This particular reference features a stainless steel case measuring 40 mm in diameter, housing the self-winding caliber 240 PS IRM C LU. This movement is known for its slim profile, achieved through the integration of a micro-rotor, contributing to the watch's comfortable wearability. The watch is fitted with a sapphire crystal and offers a water resistance of 60 meters, with a power reserve of approximately 48 hours.

For collectors, the 5712 represents an accessible entry into Patek Philippe's complicated timepieces, offering a range of functions without the complexity of a perpetual calendar or chronograph. Its stainless steel construction and integrated bracelet provide a robust and versatile option, appealing to those seeking a daily wearable complicated watch. The reference has been in production since 2006, with the 5712/1A denoting the stainless steel bracelet variant.

The IWC Portuguese Chronograph reference 3712 represents the brand's approach to classical chronograph design within the Portuguese collection. This reference features a blue dial configuration and positions itself as a dress chronograph option within IWC's offerings.

The 40.9mm stainless steel case houses an automatic movement and is fitted with sapphire crystal. The fixed bezel maintains clean lines consistent with the Portuguese aesthetic, while the watch provides 30 meters of water resistance. The blue dial serves as the defining visual characteristic of this particular reference within the chronograph series.

Reference 3712 appeals to collectors seeking a refined chronograph with contemporary sizing and automatic functionality. The stainless steel construction and blue dial combination offers accessibility within the Portuguese chronograph range, making it suitable for those wanting IWC's chronograph capabilities in a versatile package that balances sporting function with dress watch sensibilities.