The Lenovo ThinkCentre M900 is a business-class desktop computer that’s part of Lenovo’s ThinkCentre series. While my information is accurate up to September 2021, I can provide you with a general description of what the ThinkCentre M900 typically offers based on its historical specifications and features up to that point:

1. Form Factor: The ThinkCentre M900 comes in various form factors, including small form factor (SFF) and mini tower, designed to cater to different space requirements and business needs.
2. Processor: It’s typically equipped with Intel Core i5 and i7 processors, offering a balance of computing power suitable for office tasks and more demanding applications.
3. Memory: The system generally supports DDR4 memory configurations, providing efficient multitasking capabilities and smoother performance.
4. Storage: Depending on the configuration, the ThinkCentre M900 usually offers options for traditional hard drives, solid-state drives (SSDs), or a combination of both, contributing to faster boot times and application loading.
5. Graphics: The ThinkCentre M900 often includes integrated Intel HD Graphics for standard office tasks. Some models might offer discrete graphics options for more advanced graphics needs.
6. Connectivity: The desktop typically provides various connectivity options, including USB ports (including USB 3.0 and newer versions), DisplayPort or HDMI outputs for monitors, audio jacks, Ethernet port, and potentially Wi-Fi capabilities.
7. Security: Security features are a common focus in the ThinkCentre series. The ThinkCentre M900 usually includes hardware-level security features like Trusted Platform Module (TPM), secure boot, and hardware-based encryption to protect sensitive data.
8. Manageability: It’s designed to be easily managed within corporate IT environments, often offering features like remote management capabilities, compatibility with management tools, and Lenovo’s management solutions.
9. Expansion: The ThinkCentre M900 often provides options for expansion through additional PCIe slots, drive bays, and support for adding extra RAM modules, allowing for customization and scalability.
10. Operating System: The computer might come with an operating system pre-installed, often Windows, although configurations can vary.

The Lenovo ThinkCentre M900 is targeted at businesses seeking reliable and efficient desktop solutions with a focus on security and manageability. To get the most accurate and up-to-date information, I recommend checking Lenovo’s official website or contacting their customer support.