The Apple Watch stands out as a leading wearable device, yet many users remain unaware of all its integrated functionalities. One common point of curiosity is the small hole visible on the side casing of the device.

Many consumers speculate that this opening might function as a physical reset button or perhaps house a tray for a SIM card. However, Apple Watch models do not feature a physical reset button or a SIM card slot.

The Threefold Purpose of the Side Aperture

The actual reason for this opening is threefold, serving essential functions for communication and health monitoring across all Apple Watch versions.

Audio Input and Output

Primarily, this hole is the location for the Apple Watch's integrated speaker and microphones. This placement is vital, enabling users to conduct phone calls, interact with Siri, and capture audio recordings directly from the wrist.

Furthermore, some of these microphones assist in a key health feature: monitoring ambient noise levels. This helps the watch alert users to potentially harmful loud sounds.

Water Depth Measurement on Advanced Models

On newer Apple Watch models equipped with enhanced water resistance capabilities, the hole serves an additional, more specialized purpose. It is utilized to measure the surrounding water depth.

This depth measurement capability provides important data for swimming activities and helps users understand the operational limitations of their device. Most Apple Watches carry a water resistance rating up to 40 meters (130 feet).

Technical Details and Model Variations

While Apple documentation does not explicitly detail the exact mechanism, it is highly probable that sensors are situated near the microphones within this opening. These sensors work in conjunction with the Depth app on the watch to accurately measure and display water data.

It is important to note that not all Apple Watch variants support depth measurement or diving functionality. Users should verify their model before engaging in deep-water activities.

If you own an Apple Watch Ultra or a newer model, Apple confirms water resistance up to 40 meters. Conversely, older devices, such as the Series 2, are suitable for swimming but lack specific depth ratings. Using non-rated watches for diving could potentially damage the smartwatch.