# Technical data
## Memory
Efento loggers are equipped with built-in memory capable of storing up to 40,000 records. When the memory becomes full, the oldest records are automatically overwritten by new ones (circular buffer).
The length of time this memory can cover depends on the measurement interval, which is user-configurable from 1 second to 10 days.
## **Battery**
Efento loggers are powered by a single AA‑size battery (ER14505) with 3.6 V and 2700 mAh capacity. More information on: [battery safety](/efento-ble-loggers/general-information/safety-guidelines.md#battery-safety), [battery replacement](/efento-ble-loggers/installation/replacing-the-battery.md), and [proper disposal](/efento-ble-loggers/installation/replacing-the-battery.md#general-notes).
## Measured values
Efento loggers are capable of monitoring a broad range of physical and environmental parameters. Each logger can support up to six channels, each assigned to a dedicated sensor or probe. Devices can measure over 25 different parameters, including temperature, humidity, air pressure, differential pressure, open/close status, pulse counts, VOC levels, and water leakage.
All features described in this manual apply to every sensor model, while some sensors offer additional model-specific configuration options, such as calibration.
For the complete and up-to-date list of supported sensors, including their accuracy and measurement ranges, visit [getefento.com](https://getefento.com/product-categories/bluetooth-low-energy-sensors/).
## Bluetooth Low Energy
Efento loggers use Bluetooth Low Energy (BLE) to transmit data. They utilize both BLE advertising and BLE connections for communication.
## **Types of enclosures**
Efento loggers are available in two enclosure types: **IP30** and **IP67**, each suited for different environments and measurement needs.
{% hint style="info" %}
**General guidelines for choosing the enclosure type:**
* For precise environmental measurements using the logger’s internal sensors, select **IP30**.
* If the logger will be exposed to moisture or harsh conditions, select **IP67** and use external probes.
{% endhint %}
### **IP30 Enclosure**
#### **Characteristics**
* **Protection level:** protected against solid objects larger than 2.5 mm, such as tools and thick wires, no protection against liquids
* **Airflow:** Allows free airflow, making it suitable for loggers that measure temperature, humidity or air quality using built-in sensors
* **Use cases:** Indoor environments, including offices, warehouses, laboratories, server rooms or other sheltered indoor environments
* **Material:** ABS, inflamable
* **Mounting**: 3M adhesive pad with acrylic glue
* **Advantages:**
* Provides the best measurement accuracy for built-in environmental loggers
* Smaller size, suitable for indoor use
#### Size
### **IP67 Enclosure**
#### **Characteristics**
* **Protection level:** Fully dustproof and waterproof.
* **Airflow:** The enclosure is airtight and does not allow airflow. Therefore, IP67 devices cannot be used for built-in measurements of temperature, humidity, or air quality. IP67 devices must use external probes when environmental monitoring is required.
* **Use cases:** Industrial environments, outdoor installations, places exposed to moisture, wash-downs, dust, or chemicals
* **Material:** ABS, inflamable
* **Mounting**: screws or cable ties
* **Advantages:**
* Provides strong protection against water and dust
* Suitable for installation in harsh environments or outdoor
#### Size
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