## Common ground
All options are devices that detect or locate objects, people, or hidden features using electronic sensing.
## Options at a glance
**8526.91 – GPS/GPRS trackers**
- **Defining trait:** Uses satellite and cellular networks for real-time remote tracking of moving objects.
- **Typical examples:** Car GPS trackers, smartwatch-based location tags.
- **Best fit when:** Tracking vehicles or assets over long distances with live updates.
**8531.80 – RF/Bluetooth key finders**
- **Defining trait:** Uses short-range wireless signals (RF or Bluetooth) to locate small personal items like keys or wallets.
- **Typical examples:** Tile, Apple AirTag, Samsung SmartTag.
- **Best fit when:** Finding lost everyday objects within a few meters.
**8543.70 – Presence detectors & utility locators**
- **Defining trait:** Detects movement (PIR/ultrasonic) or hidden utilities (cables/pipes) using passive sensors or electromagnetic fields.
- **Typical examples:** Motion sensors, underground pipe locators, stud finders.
- **Best fit when:** Locating people in a room or finding buried infrastructure.
**9030.33 – Live wire locators (no recording)**
- **Defining trait:** Detects live electrical wires, metal, or wood without storing data.
- **Typical examples:** 3-in-1 voltage/wood/metal detectors for DIY use.
- **Best fit when:** Immediate on-site safety checks without logging.
**9030.39 – Live wire locators (with recording)**
- **Defining trait:** Same as above but includes data storage for later review.
- **Typical examples:** Professional-grade electrical testers with memory logs.
- **Best fit when:** Need to document findings for safety or compliance.
**9031.80 – Motion-based asset trackers**
- **Defining trait:** Monitors motion to track location of pets, valuables, or assets over time.
- **Typical examples:** Pet collars with movement alerts, secure box trackers.
- **Best fit when:** Monitoring status (movement vs. stillness) of valuable items.
## Key differences
| Option | Primary Tech | Range | Data Storage | Main Use Case |
|-------|--------------|--------|----------------|----------------|
| 8526.91 | GPS/GPRS | Long | Varies | Real-time remote tracking |
| 8531.80 | RF/Bluetooth | Short | No | Finding lost small items |
| 8543.70 | PIR/Ultrasonic, EM | Medium | No | Detecting presence or utilities |
| 9030.33 | Voltage/metal detection | Short | No | Immediate safety checks |
| 9030.39 | Voltage/metal detection | Short | Yes | Safety documentation |
| 9031.80 | Motion sensing | Medium | Yes | Asset movement monitoring |
## How to choose
- Does it use GPS or cellular networks? → 8526.91
- Is it designed for small items like keys, within short range? → 8531.80
- Does it detect motion or presence in a room? → 8543.70
- Is it used to find live wires, metal, or wood on-site? → 9030.33 or 9030.39
- Does it record location or movement data over time? → 9031.80
## Overlaps & pitfalls
- **Overlaps:** 9030.33/39 and 8543.70 both detect hidden wires/metal; use depends on whether it’s for safety (9030) or utility mapping (8543).
- **Pitfall:** "Object locator" is vague—some options track motion, others detect static presence. Prioritize the **main function**: real-time tracking vs. detection vs. monitoring.
- If unsure, choose based on **primary purpose**: location (GPS), proximity (Bluetooth), safety (voltage), or movement (motion sensor)