Pre-installed soft
The navigation programme, originally installed in the navigator and sold with it, in other words, a set of maps available to the user “out of the box”.
Most modern navigators are equipped with such programs (although the name of pre-installed maps is not indicated for all models). Note that the functionality of complete programs in different models may vary. Most often, these are the simplest maps of the world or the region in which this device is sold. However, there are exceptions: there are models with detailed maps, programs with advanced functionality, etc. Such exceptions are especially common among high-end specialized devices, in particular marine and aviation (see "Scope"). And for some navigators, there may be several options for pre-installed programs and even the ability to select such programs at the request of the user. All these details should be specified in each case according to the manufacturer or seller.
It is also worth considering that the characteristics often indicate only the general name of the cards. At the same time, the same card can be available in several versions that differ in functionality and, sometimes, terms of use (paid / free). However, the main features are basic capabilities, interface device, etc. — usually, are common to all versions. Therefore, by the name of the complete programme, usually, one can quite accurately determine the general capabilities and features of the card's functionality.
Built-in memory
The amount of built-in memory installed in the navigator.
The amount of data that can be stored in the device directly depends on this indicator. However, it is worth keeping in mind that, on the one hand, a certain amount of built-in memory will inevitably be occupied by the operating system (if there is one), firmware and other programs supplied in the kit; on the other hand, the set of these programs in most cases also includes a preinstalled card. The latter means that the navigator can be used for its intended purpose “out of the box” without installing additional software; and for such an application the built-in memory is guaranteed to be enough. This means that it makes sense to pay attention to the storage capacity primarily if the device will have to work with additional data - from extended maps to photos and videos. This is especially true for models with a full-fledged OS like Windows or Android, which allows the installation of additional applications.
Max. memory card / flash drive size
The maximum size of a memory card or USB-drive (flash drive) supported by the navigator.
Removable media can be used for different purposes: downloading maps and software updates, uploading tracks you have covered, playing or copying music and movies (in models with the appropriate capabilities), etc. Specific options for using such media for each model should be clarified separately. And the restrictions on volume are primarily due to the fact that more capacious memory cards and flash drives require more powerful hardware. So you should not exceed this limit: at best, the drive will not work correctly, at worst, hardware failures are possible.