These adaptors will allow your device to be attached to almost all Daessy Quick-Release Bases. The exception is that Daessy holders/adaptors are not designed to fit onto Wedge Quick-Release Bases. Those new Wedge QRBs are only compatible with devices that already have Wedge (non-Daessy) adaptors.
Adaptor Plates are usually attached onto the back of your device. This is typical for most communication aids.
Holders provide a case with a Daessy adaptor attached. These are mostly used for iPads or other thin tablets.