I have the POB HID, 15mcp Thor, Pro's Favorite 17.5mcp, and a "Sharper Image" brand 10mcp spotlight that seems to be a 10mcp Thor with some added features.
The POB HID should be quite a bit smaller than the POB 10mcp. My 10mcp spotlight is much larger than the POB HID.
My 15mcp Thor is twice as large as the POB HID. The Harbor Freight HID would be about the same size as the 15mcp Thor, so at least twice as big as the POB HID.
The Pro's Favorite is a bit larger than the 15mcp Thor so it looks over twice the POB HID's size.