High Low Impedance Adapters?

I had a stereo system installed in my truck.  Idid not like the installation so i'm redoing some of the wiring myself. My question is what are the two high low impedance adapters for behind the haed unit?  Is it for switching from regular copoer paired wire to RCA cables that go to my 4 channel amp?

Thanks, Monty

Actually these do change impedence too.

The main purpose is to attenuate the speaker level voltages to something more friendly to the amplifier RCA (line-in) inputs.

The speaker level happens to be around 4 ohms impedence and the line-out/line-in are somewhere around 100 ohms, it's helpful for the LOC to have a similiar impedence at it's output side. They must've installed these because your stereo has no line-out RCA connections.

My question is: what don't you like about the install and why are you changing it around? At least you asked befoire you started ripping stuff apart, I'm not knocking you for what you're doing. I'm just curious as to why you aren't asking the shop for a refund or having the problems fixed? Did they mess your car up that bad?

Thanks You for your responses.

Actually I could have returned to the install shop, but i had to return a couple of times for them to replace sub when it went out, and have them redo the power cable from the battery because it was routed through my emergency brake pedal, and return for one of the speakers not working.  They corrected all of these with no objection , but my time is valuable and to expensive for me to get all defensive.

So I checked the rest of the installation and didn't like the way some of the wires were spliced. plus a friend offered  me a better stereo to repay me for a electrical job i did for him.  So when I removed the installed head unit I noticed the pyramid units. So I didn't remove them, I reconnected them and every thing works great.

I have a four channel amp for my four speakers and a two channel amp for my subwoofer that is being fed from the RCA output on my unit.

Cool, too bad you had to see the ugly side of the 'professional' mobile electronics industry.

The person who did your car is probably getting minimum wages and has next to no training.

I take it you are an electrician or electronics professional? Time is money, but sometimes it's best to take matters into our own hands.

I've seen a professional automotive electric shop take weeks to figure out a computer problem while I had it figured out in minutes. I didn't even know the car that well, I only looked at a block diagram in the service manual and figured the obvious fault with the given symtoms. My friend still payed $1100 for diagnostics and replacement of new transistor pack and engine computer. That's why I never take my car to the shop! 

I guess he only would've saved $800 and three weeks of time, might as well have the professionals handle it!