diff --git a/src/ble-device-info-service/protocol.ts b/src/ble-device-info-service/protocol.ts
index b94296ae..b1dfb101 100644
--- a/src/ble-device-info-service/protocol.ts
+++ b/src/ble-device-info-service/protocol.ts
@@ -31,9 +31,13 @@ export enum PnpIdVendorIdSource {
  * Decoded data from the PnP ID characteristic.
  */
 export type PnpId = {
+    /** For Pybricks hubs, this should be PnpIdVendorIdSource.BluetoothSig */
     vendorIdSource: PnpIdVendorIdSource;
+    /** For Pybricks hubs, this should be LegoCompanyId (from ble-lwp3-service/protocol). */
     vendorId: number;
+    /** For Pybricks hubs, this should be one of HubType (from ble-lwp3-service/protocol). */
     productId: number;
+    /** For Pybricks hubs, this should be hub variant if applicable (from ble-lwp3-service/protocol). */
     productVersion: number;
 };
 
diff --git a/src/ble-lwp3-service/protocol.ts b/src/ble-lwp3-service/protocol.ts
index 4ddb149d..b9223cef 100644
--- a/src/ble-lwp3-service/protocol.ts
+++ b/src/ble-lwp3-service/protocol.ts
@@ -5,6 +5,13 @@
 //
 // https://lego.github.io/lego-ble-wireless-protocol-docs/
 
+/**
+ * LEGO's Bluetooth SIG company identifier.
+ *
+ * https://www.bluetooth.com/specifications/assigned-numbers/company-identifiers/
+ */
+export const LegoCompanyId = 0x0397;
+
 /**
  * LEGO Powered Up Hub type IDs
  *