The MK3-USB allows the following products to connect to a computer for configuration and firmware updates:

Multi, MultiGrid, MultiPlus, MultiPlus-II, Quattro, VE.Bus BMS V2, Inverter/Charger settings in ECOmulti, EasySolar, EasyPlus, and Inverters with a VE.Bus communication port.

DIMENSIONS
Weight:1.59 lbs
Depth:3.94 in (10.0 cm)
Width:7.87 in (19.9 cm)
Height:1.18 in (2.99 cm)

Manual