1S1
The 1S1 is a sampling plug-in for 500-series scopes. It has its own trigger and timebase. The oscilloscope's timebase is usually set to a relatively slow sweep rate when using a 1S1. The 1S1 has a 50-Ohm GR connector for signal input. The plug-in supplies power to, for example, a P6032 cathode follower probe.