# What is a Prefixed Module?

In the PrestaShop world, extensibility revolves around modules, which are small programs that use PrestaShop’s functionalities. These programs change the functionalities or add to them to make PrestaShop easier to use and tailored to the merchant’s needs.

To include Composer dependencies and avoid naming conflicts with other modules, PHP-Prefixer provides a way to prefix all PHP files with a custom prefix for the project.

In this guide, we will create the Hello PrestaShop Products Module, based on the Friends of Presta/products (opens new window) module. The module demonstrates all available customizations in Product pages (e.g., adding a new "alternative description" field in the catalog). Thanks to Friends of Presta/Mickaël Andrieu (opens new window).

The Products already integrates a Composer dependency, the tightenco/collect (opens new window) library, to integrate the Illuminate Collections library, "a fluent, convenient wrapper for working with arrays of data."

This is how the modified Hello PrestaShop Products module looks after the prefixing process with the new PPP namespace:

namespace PsProducts;

use PPP\Tightenco\Collect\Support\Collection;

 * Manage a ProductsCollection instead of a collection of Products array.
class ProductsCollection extends Collection