The A40 is a high bandwidth attenuator, which can measure multiple single-ended signal, such as DC, AC, pulse.
                                                    
                                                    The A10 is a high bandwidth attenuator, which can measure multiple single-ended signal, such as DC, AC, pulse.
                                                    
                                                    The A20 is a high bandwidth attenuator, which can measure multiple single-ended signal, such as DC, AC, pulse.