RTM SM911 is the famously improved RMGI EMTEC tape which offers more headroom plus a 3dB higher input/output and a smoother surface than older tapes. It has a coated back and the no-dropout-technology makes this the ultimate and most sold studio Master tape. There is no reason for buying 30 year old NOS tapes ? RMGI SM911 tapes are more cost efficient and rank higher in overall quality.