Slices maintained for many hours in incubating media - Four separate rings allow separation of different types of preparations - Slices supported on a quick change nylon net. The BSK4 Brain Slice Keeper has been designed to pre-incubate a large number brain slices prior to transfer into recording chambers or for the incubation of preparations in experimental test media. Based on the BSK1, it consists of four closely fitting acrylic rings, located in a circular manifold, between which is wedged a removable sheet of nylon netting. In operation, the four rings located on a manifold with netting are totally immersed in an ACSF-filled purpose designed holding vessel into which a 95% O2, 5% CO2 gas mixture is supplied through a ceramic bubbler.