The BitWizard boards exist in both an SPI as well as an I2C version. Both versions have the same default address.
Especially if you have more than one board of the same type you can change the default address to something else that you like. See the relevant protocol page for info on how to do that.
|Temp (sometimes called SPI_LM35)||0x8C|
|RPI SPI Relay||0xA6|
|High Side Switch||0xA8|