The FF-CAD is a Codec-based Audio Delay module which has many features which set it above other delay module designs:
FF-CAD Pricing

FF-CAD Specifications

Power requirement+9.0 to +12 volts @ 50 mA
Digital signals:
MUTE1, Delay Inhibit0 - 5V
MUTE20 - 40V
Analog signals
Audio input level0 - 3.0 Vrms
Input and Output CouplingAC
Input impeadance100 Kohm (50Kohm w/ DTMF option)
Audio Output leveltracks input level
Audio Output impeadance1Kohm
Output noise floor69 dbV (0.3 mV)
Intermod Distortionbetter than -50 db
Passband response(200hz-3khz)+/- 0.1 db
Board dimensions2.8" x 4.6"
Maximum delay (Factory standard)250 msec
Note: maximum delay may be user modified (via cut jumpers) to either 500ms or 1 second