The experimental apparatus used at intersection 1 by the CERN-Columbia-Rockefeller-Saclay Collaboration (experiment R 105). It consisted of two almost identical magnetic spectrometers centered at 90ᵒ on opposite sides of the intersection region. In each spectrometer one can see magnetostrictive wire spark chambers, a magnet, more chambers and various hodoscopes of scintillation counters. Gas Cerenkov counters were located in the gap of each magnet. On the left hand side, a matrix of 119 lead glass Cerenkov counters was located behind some concrete and iron shielding blocks.