While the product description on Amazon says these are outdoor speakers, the actual packaging does not. There is one small image on the box with a caption saying they are for outdoor use, but it has an asterisk. The fine print on the bottom of the package says "weather permitting, speakers are not water resistant." I bought these as outdoor speakers based on the description on Amazon.
On top of that, there is no way to turn the speakers off, so they will constantly drain the C batteries, and taking the batteries out to prevent draining requires removing four screws.
The connection for the transmitter is either RCA plugs or a headphone jack. My receiver doesn't allow for RCA plug outputs (and most only have one set) requiring the headphone jack to be used. Unfortunatley my (and most) stereo(s) turn off the main speakers when a plug is inserted in the headphone jack. So I have to choose between listening to the outdoor speakers and the indoor, rather than use both at the same time. This is no good for parties, since I want music both indoors and out.
Overall, these speakers do not serve their purpose whatsoever.