Gibraltar GAS-2X4 Amp Shield Sound Shield For Half Stack PanelIsolates your guitar amp sound in the studio and controls it onstage. The Gibraltar Amp Shield is just what you need for sound control. Place these Plexiglas walls in front of your guitar amps to block the sound from hitting the audience or recording room head on. The GAS Amp Shield is especially useful in applications where the amplifier is mike, since you can crank the amp without worrying about balancing the mix.