I purchased this receiver new and it was used in a smoke-free, kid-free home for a few years.  It is in like-new condition.  

Everything that was originally included in the box is here:  remote, antenna, user manual, quick start guide, original box.

See below for details I pulled from Crutchfield:



About the Onkyo TX-SR606

Dave Bar

Onkyo's advanced TX-SR606 delivers outstanding audio and video performance from today's newest generation of high-def components. This receiver gives you plenty of HDMI inputs along with sophisticated processing for a cutting-edge home theater experience. For example, it can decode Dolby® TrueHD and DTS-HD® Master Audio — two new high-resolution surround sound formats found on many newer Blu-ray players and discs.

Flexible HDMI switching with video upconversion to 1080i
The 'SR606's 1080p-compatible HDMI inputs let you hook up four high-def sources and switch easily among them, while maintaining pristine digital sound and picture quality. This receiver can also upconvert your non-HD sources to an HDMI signal with up to 1080i resolution. That means you can route all your video components through your receiver and make a single cable connection to your HDMI-equipped HDTV.

Fast, accurate setup
The 'SR606 includes Audyssey 2EQ, a sophisticated speaker calibration system that makes it simple to optimize surround sound for your room. Using the included microphone, the receiver analyzes sound from two different listening positions, then automatically adjusts level, equalization, and delay settings for each of your speakers. The result is clear, precise, natural sound.

Flexible entertainment options
This receiver's dual-room/dual-source audio capability lets you enjoy home theater in your main room while a housemate listens to stereo music in a second room. You can integrate your iPod® by adding Onkyo's handy control dock, and tune in to SIRIUS Satellite radio with the addition of an optional SiriusConnect™ home tuner kit.

Read our blog post My wish list -- the Onkyo TX-SR606 home theater receiver

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Product highlights:

  • 90 watts x 7 into 8 ohms (20-20,000 Hz) at 0.08% THD
  • Dolby® TrueHD, DTS-HD™ Master Audio, Dolby® Digital Plus, DTS-HD™ High Resolution Audio, Dolby Digital EX, DTS-ES®, Pro Logic® IIx, and DTS Neo:6 decoding
  • SIRIUS satellite radio capable (requires SIRIUS subscription and optional SiriusConnect™ home tuner kit)
  • iPod integration (requires optional Onkyo DS-A3 iPod dock)
  • Audyssey 2EQ auto speaker setup (microphone included)
  • Audyssey Dynamic EQ for better surround sound at lower volumes
  • dual-room/dual-source audio (powered and line-level stereo audio output for 2nd room; using powered 2nd-room output allows 5.1 home theater in main room)
  • RIHD (Remote Interactive over HDMI) simplifies system control with compatible Onkyo components
  • back surround speaker channels re-assignable for bi-amping front left and right speakers
  • high-current amplifier design
  • 192kHz/24-bit digital-to-analog converters for all channels
  • 40 AM/FM/SIRIUS presets
  • aluminum front panel
  • multibrand remote
  • sleep timer (via remote)
  • 17-1/8"W x 6-7/8"H x 15-1/16"D
Connections:
  • 1080p-compatible HDMI digital video switching (4 in, 1 out)
  • HDMI version 1.3a with support for x.v.Color™ and HDMI-CEC with compatible video sources and TVs, Auto Lip Sync
  • analog-to-HDMI video upconversion with scaling up to 1080i
  • component video switching: 2 in, 1 out
  • digital inputs: 2 optical , 2 coaxial
  • 5 audio/video inputs, including:
    • 1 front-panel input with composite video
    • 4 rear-panel inputs with composite and S-video
  • 2 audio-only inputs
  • no phono input
  • 7.1-channel analog audio preamp input
  • 1 pair of main speaker outputs
  • MFR # TXSR606

What's in the box:

  • Black AM/FM/Dolby Digital/DTS receiver
  • Wireless remote control (RC-710M)
  • 2 "AA" batteries
  • AM loop antenna
  • FM wire antenna (with push-on "F" connector)
  • Speaker setup microphone with attached 19.5' cable (3.5mm mono mini-plug terminal)
  • Instruction Manual
  • Quick setup guide
  • Remote control code chart
  • Product registration card/Warranty information
  • Interactive iPod dock information
  • Using Sirius Satellite Radio instructions
  • Sirius Satellite Radio brochure
  • Sheet of adhesive labels
  • RIHD instruction sheet