<!--
{
  "availability" : [
    "macCatalyst: 14.0.0 -",
    "macOS: 10.15.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "IOUSBHost",
  "identifier" : "/documentation/IOUSBHost/IOUSBHostIOSourceDescriptors/sspCompanionDescriptor",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "IOUSBHost"
    ],
    "preciseIdentifier" : "c:@S@IOUSBHostIOSourceDescriptors@FI@sspCompanionDescriptor"
  },
  "title" : "sspCompanionDescriptor"
}
-->

# sspCompanionDescriptor

The descriptor for a SuperSpeedPlus isochronous USB endpoint companion.

```
var sspCompanionDescriptor: IOUSBSuperSpeedPlusIsochronousEndpointCompanionDescriptor
```

## Discussion

This descriptor may be necessary for `bcdUSB` versions 0x0300 and greater, depending on device operating speed and values set in the descriptors. See USB 3.2, 9.5 for more information.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)