Products for the Intelligent Musician The eStrapTM Strap-Controlled Expression System Concept by Ned Steinberger. Free your feet, free your music! The ZEROCAPTM Cable Capacitance Eliminator Hear your guitar for the first time. PM-150 Audio Power Meter Accurate power measurement for working musicians. The Z-TunerTM with Knife Edge TuningTM Convenient, accurate tuning for just about any guitar or bass. The S-TunerTM with Knife Edge TuningTM Convenient, accurate tuning for your Fender® Stratocaster® or compatible.