diff --git a/messages.go b/messages.go
index a8e73d3..55fff57 100644
--- a/messages.go
+++ b/messages.go
@@ -966,10 +966,23 @@ type StatusMessage struct {
 	States map[string]bool `json:"states,omitempty"`
 }
 
+type ManufacturerDataElement struct {
+	// The company ID, which must be one of the assigned company IDs.
+	// The full list is in here:
+	// https://www.bluetooth.com/specifications/assigned-numbers/
+	// The list can also be viewed here:
+	// https://bitbucket.org/bluetooth-SIG/public/src/main/assigned_numbers/company_identifiers/company_identifiers.yaml
+	// The value 0xffff can also be used for testing.
+	CompanyID uint16 `json:"company-id,omitempty"`
+
+	// The value, which can be any value but can't be very large.
+	Data []byte `json:"data,omitempty"`
+}
+
 type BleAdvertisementPayload struct {
-	LocalName        string            `json:"localName,omitempty"`
-	Bytes            []byte            `json:"bytes,omitempty"`
-	ManufacturerData map[uint16][]byte `json:"manufacturerData,omitempty"`
+	LocalName        string                    `json:"localName,omitempty"`
+	Bytes            []byte                    `json:"bytes,omitempty"`
+	ManufacturerData []ManufacturerDataElement `json:"manufacturerData,omitempty"`
 }
 
 type BleDevice struct {