This is a very nice, clean Timewave model # DSP-59+ Audio Noise Reduction Filter. This is the later "Plus" version of the DSP-59 series. It came with a large group of equipment from a local sale (including a Timewave DSP-599zx that I'll be listing later.) See the on-line reviews of this unit - it provides excellent filtering for received CW, RTTY, digital signals. It requires a +12V DC wall-wart, not included, the manual is included. $100, payment by check or money order, no PayPal, no trades. Please email any questions to my address firstname.lastname@example.org as shown on QRZ.com, instead of using QRZ.com's message system. The manual is also available for free on-line download, if you have any questions about the installation, use and specificiations of this DSP-59+.