This is a Wireless Unit for either a guitar or bass. It is used, but I have only had it for about five months. I have used it at band practice, and found it to be reliable and fun, just not really something I need. I do not have the box, or the operating manual. The manual can be downloaded from the internet, but the unit is super easy to use.
Here are some specs:

System 8 Wireless Systems are designed for reliable performance, easy setup and clear, natural sound quality. The ATW-801/G-T3 system includes the ATW-R800 receiver and ATW-T801 UniPak transmitter with a AT-GcW guitar/instrument cable.

This system transmits on the T3 band. The band is fixed, and if you are getting multiple systems, you'll want to be sure that each system occupies a different band.

A novel "dipole" antenna system on the receiver improves operation by providing a "ground" element in addition to the usual "signal" element. Line-of-sight operation is good to about 200 feet.

The System 8 Wireless lavalier system is a well-made, reliable, good-sounding wireless solution from one of the leaders in wireless audio technology, introduced at an affordable price. There are cheaper wireless systems on the market, but many of them lack depth and presence. The System 8 is professionally presentable for ministers, auctioneers, business speakers and teachers of all kinds.
Consumer Alert:
Most users do not need a license to operate this wireless microphone system. Nevertheless, operating this microphone system without a license is subject to certain restrictions: the system may not cause harmful interference; it must operate at a low power level (not in excess of 50 milliwatts); and it has no protection from interference received from any other device. Purchasers should also be aware that the FCC is currently evaluating use of wireless microphone systems, and these rules are subject to change. For more information, call the FCC at 1-888-CALL-FCC (TTY: 1-888-TELL-FCC) or visit the FCCs wireless microphone website at: www.fcc.gov/cgb/wirelessmicrophones.
FEATURES
Easy operation and clear, natural sound quality
Reliable performance and durable construction
Advanced dipole antenna system for extended operating range
Power, RF, and AF Peak indicators
Volume control, 1/4" output jack and user-adjustable squelch
AA operation on transmitter
Order today and experience stage liberation.
SPECIFICATIONS
System 8 Wireless System includes: Guitar/Instrument

Operating Frequency: VHF highband, 169 MHz to 172 MHz
Modulation Mode: FM
Maximum Deviation: +/-10 kHz
Dynamic Range: >/=90 dB (A-weighted), typical
Total Harmonic Distortion: <1% (at 1 kHz, +/-10 kHz deviation)
Operating Range: 200' (60 m) typical
Operating Temperature Range: 40 F (4 C) to 110 F (43 C)
Frequency Response: 80Hz to 13kHz

RECEIVER SPECIFICATIONS

Receiving System: Non-diversity, single-channel, dual antenna system
Image Rejection: 50 dB minimum
RF Sensitivity: 20 dBuV at 60 dB S/N ratio (50 ohms termination)
Audio Output: 1/4" (6.3 mm), unbalanced: 700 mV (1 kHz modulation, 10 kHz deviation, 100k ohm load), nominal
Power Supply: 100-240V AC (50/60 Hz) to 12V DC .5A (center positive) switched mode external power supply
Dimensions: 7.48" (190.0 mm) W x 1.82" (46.2 mm) H x 5.06" (128.5 mm) D
Net Weight: 11.8 oz (335 grams)
Accessory Included: Power supply