AmpPRO simplifies the installation of upgraded amplifiers in data-bus controlled amplified sound systems. With AmpPRO. you can improve audio performance while keeping an original radioaƒÂ¢a¢â€šÂ¬ s fit. finish and features. The APA-TOS1 is a fiber-optic audio output add-on accessory for use with an AmpPRO interface. The APA-TOS1 easily installs in your AmpPRO interface and instantly provides a digital Toslink output. APA-TOS1 is compatible with any brand and length of Toslink cable for connection into a Toslink equipped DSP. or amplifier. Simplify speaker wire connections when adding aftermarket amplifiers with our Speaker Connection Harness. Amplifiers can be easily added with no need to cut or modify a vehicleaƒÂ¢a¢â€šÂ¬ s original wiring.