The SOL80SPDR3P08 is a terminal extension for the Schneider Electric EasyPact Solar MCCB 800 range — a 3-pole block rated 400-630 A, built with copper conductors and an 80 mm connection pitch. It mounts straight and connects both upstream and downstream on the breaker. That 80 mm pitch matches the standard busbar or cable-lug spacing for this frame size, so you're not fighting alignment on the panel backplate.
The 400-630 A rated current covers the full EasyPact Solar MCCB 800 frame — you're not buying a separate extension for every breaker amp rating in that family. Copper conductors keep voltage drop predictable at full load; aluminum busbar adapters aren't needed unless your system is spec'd for aluminum. Three-pole configuration matches the standard 3P MCCB; if you're working a 4-pole breaker, this isn't the extension you need.