The Siemens 6ES7790-0AA01-0XA0 is a SIMATIC PC optical USB mouse with three buttons and a scroll wheel, bundled with a PS/2 adapter for use on SIMATIC programming devices and industrial PCs. This is a peripheral for the SIMATIC PG/PC line — the same form-factor and interface used on Siemens field programmer units — so it's a drop-in replacement for a lost or worn-out OEM mouse that came with the system.
For a sourcing buyer, mature lifecycle means the part is available through normal Siemens distribution channels without the premium of a last-time-buy or the scarcity of an obsolete line. It's a standard quoted-to-order item against an RFQ.
The optical USB mouse connects via a standard USB port on any SIMATIC PG or industrial PC, and the included PS/2 adapter gives backward compatibility with older programmer units that lack USB. The three-button wheel design is the standard industrial HID — no special driver needed for basic operation on Windows-based SIMATIC systems.