Help Identify Install Edge parts?

I am adding external amp to my daughters car which has a Pioneer DEH-3400: I will be driving the front speakers and the sub with the amp and new rear speakers off the H/U internal amp.

In the process, I found that the installer has used an in-line component on the amplified speaker outs - they are a cylinder about 1/2" diameter by about 2" long with a white shrink wrap over them with the Install Edge logo on them: What are these - anyone know? I imagine they must be some kind of noise/isolation device?

Not going to affect the install, but just curious.

Incidentally, I find that the RCA pre-outs on this head are for the REAR O/P's - what's with that ???? That means to use the amp on the front speakers I need to switch the H/U amplified O/P's from the rear to the front to drive the rear speakers, so the fader will now be reversed - what kind of logic would have applied the pre-outs for the rear channels? Isn't that a bit strange or was that typical?

The cylinders are passive crossovers. They block lower frequencies to protect your midrange speakers.

I am assuming that the HU is an older model. The only reason I can think of for the RCA's being "rear" outputs is that lower frequencys/bass have generally been associated with the rear of a vehicles sound system. The first upgrade that most people make to their sound system is a sub, so I guess pioneer thought it would be best to do it that way. It makes a little bit of sense, but only if you assume that most people will never add an amp to their highs. You could always use an LOC if it becomes too much of a nuisance, or get a new HU.

Thanks for a very quick reply! I hadn't come across those passive crossovers on a head amplified install before, so good to know what they are: do you now what the C/O frequency cut-off is? Are these quite typical on installs with OEM speakers in lower-end car set-ups? It was driving the stock speakers on a Civic so they probably needed al the protection they could get and I'm sure would not have liked playing the low end!  With the new JL's, I would probably have taken them out, but since the sub is going in, better to leave them so as not to muddy the sub.  

A new head unit would be nice - I have already spent way more on her budget than I had intended, so that is going to have to wait for another occasion - she's already tapped out on the next few birthdays & Christmas's! The H/U is indeed an older model it appears, but has some quality features on it regarding EQ etc and the on-board amp is already driving the new rear JL Audio's & sound ing quite nice, so it will do for now.

Again, much appreciated for the speedy reply.

The color of the wires coming out of the c'o itself will tell you it's freq. I dont have them moemorized but they carry them at Best Buy. They are probably in the range of 200-400hz.

As far as I know they aren't typical in HU installs and were more than likely a tack on sale. Someone convinced the buyer that they needed them. Who knows. They aren't bad to have if you dont have another way of keeping the low freq's out.

If you have time to play with the system, I would try listening with and without the crossovers installed. It is nice to have some bass coming from the midranges, but of course it is your preference. I would at least find out what frequency they are at so you can match it with the sub.