First thing to do...the plate part is designed to fit into a cutout on the SW-Motech rear rack system; it has a 3/8" plastic piece sticking out the bottom. Our bike's rack has no such cutout, so I ground off the plastic extension on the bottom of the plate so it would sit flat on a table.
That plate could now be screwed/bolted directly onto our rear rack. But, that would involved drilling through the rack or fashioning some sort of bottom bars or plates or something. I don't want to drill into my factory rack. So I removed the silver top piece and put it on a shelf. I then used a 1/8" aluminum plate I had to make an adapter of sorts. The plate bolts into the forward factory rack holes with the help of some spacers. The pelican mounting plate bolts to the alu. plate I made.
Alum. Adapter:
I'll paint that alum. piece black eventually.
Bolted to the bike. I only had to drill one hole in the black OEM rack base:
Box with adapter installed on box:
Box mounted:
Verdict...Works like it's supposed to. It locks to the rack, and the lid locks on the case (keyed alike). The one disappointment is with the case itself. I've had Pelican boxes before. If I didn't know this one actually came from Pelican, I'd swear it was a cheap knockoff. It is lighter and not as bomb-proof feeling as the regular Pelican. This is their "Storm" line, and it is not as robust as the regular lineup. The 1550 box (similar size/shape) is different than this box. For this application, I'm ok with it since the box won't be checked as luggage or thrown around in the back of a pickup. But...if I had a choice, I'd have taken a 1550 over this iM2600 box.
I like the look, and getting this was, I admit, as much a style choice as anything else.