These tapes use an ultrafine, Super Avilyn Type II, high-bias cobalt formulation with high-density packing and uniform orientation. They offer exceptionally high resolution, superior dynamic range, and very low noise, which makes them ideal for taping from a wide variety of music sources, including CDs. TDK SA tape employs the advanced AR-RC III mechanism for superior rigidity and reduced modulation noise, and is especially recommended for use in home component systems, high-performance portables, and car stereos. Ultimate Performance Super Avilyn Type II Formulation. Super High Resolution CD Rproduction with maximum dynamic range. CD Energy Mechanism reduces modulation noise. 71 dB Dynamic Spectral Output. This is a four-pack of SA-100 high bias cassettes. Each tape has a 100 minute total recording time or 50 minutes per side.