Which of the ULT-2000 series dual conductivity probes works best with what type of soaking tray or container?

The ULT-PC-10 was specifically designed to work with the (now discontinued) Johnson & Johnson Cidex 2032 oval soaking tray.

The 2032 tray was replaced by Johnson & Johnson with a larger tray and BC Group offers the BC20-42200 Cidex Compatible Tray that is a very similar size as the Johnson & Johnson replacement for the 2032.

The ULT-PC-15 works best with both of these trays.  The ULT-PC-20 has two sets of screw-in rods and is compatible with commercial cleaning stations such as the PCI Medical GUS station, or with deep soak trays.