This is a handy SCSI switchbox - comes with desired cables - that allows you to connect two different samplers to one SCSI drive, such as a SCSI2SD External Drive. Hook up both samplers and switch between the two.
A switchbox is desirable so each sampler (a 'initiator' in a SCSI chain) are isolated from each other. Turning the knob on the front selects the sampler hooked into the back. No rebooting of the sampler is necessary.
Please indicate in the Comments section on checkout what THREE SCSI cables (which ends, e.g. DB25-CEN50) you would like to be included with your switchbox.
These switchboxes are used and may not look like the one pictured, but they are very similar and do the exact sample thing. All have a 1-year warranty.