A 'what is' question

[Herbie]

Does anyone know what the arrowed part(s) are?

It may be one thing or two, I'm not sure, but it's under the boot floor and next to the 12V Battery in my 2013 RX450h Advance.

 

[Herbie]

OK, I think I've found out what it is!

Unbelievably, it looks like the 'Rear No.3 Speaker Housing'

Talk about over-engineering - or creating expensive stuff where there's no need for it! If anyone else knows different then please post it up for all to see, but in the absence of anything else, I think it's that speaker housing:

 

 

[ColinBarber]

Yes, looks like the sub housing.