If the total load on the 6-channel dimmer will exceed 20A, you’ll need to use the larger device, the LumenDim6. The LumenDim6 can handle a maximum total load of 45A.  For all RC4 dimmers, the voltage range is 5V – 35V.  The most common voltages used in the field are 12V and 24V.

If the total load in your application is 20A or less, I recommend the much smaller LumenDimM6. The “M” means Miniature, and it’s substantially smaller than the large unit. The screw terminals on the M6 are rated to a maximum of 20A, so the bottleneck is the power input, which is a single pair of terminals.

The large unit uses 45A Anderson Powerpole connectors for the power input, and 15A connectors for the outputs, so it’s capable of handling more than double the load of the smaller M6.

Note:

• this question is relevant when comparing the 4-channel device as well. Check out this video discussing the 4-channel.
• this question is relevant when comparing across the RC4Magic 2.4GHz, Magic 900MHz, LumenDim and W-Dim product lines.