3S2
From TekWiki
The Tektronix Type 3S2 is a dual-trace sampling plug-in for 560-series scopes. It takes two 7000 and 3S series sampling heads such as the S-1, S-2, S-3, S-4, S-5, or S-6.
Bandwidth and sensitivity are determined by the sampling heads, not the 3S2.
The 3S2 uses a BSM connector for the trigger output on the front panel.