The Switch-Itt and Wilcom ROM Switcher are actually the same design.
The Switch-Itt is allows you to switch between different versions of Kickstart without having to keep removing chips and is compatible with the A500, A500+, A600, A1500, A2000 and A2500. It holds two kickstart chips and allows switching between the two by holding down CTRL-LAMIGA-RAMIGA for about 3-4 seconds. If switching to the alternate ROM is made a high pitched tone is produced and if reverting the original kickstart, a low pitch tone is produced. The SWITCH-Itt draws power from a clip that attaches to pin 18 of the 68000 CPU.