diff --git a/07-routing-gossip.md b/07-routing-gossip.md
index 48e881062..10eee0690 100644
--- a/07-routing-gossip.md
+++ b/07-routing-gossip.md
@@ -1140,7 +1140,8 @@ parameter which allows decryption of the `enctlv` field inside the
1. type: 385 (`onion_message`) (`option_onion_messages`)
2. data:
- * [`1366*byte`:`onionmsg`]
+ * [`u16`:`len`]
+ * [`len*byte`:`onionmsg`]
* [`onion_message_tlvs`:`onion_message_tlvs`]
1. tlvs: `onion_message_tlvs`
@@ -1155,13 +1156,22 @@ The writer:
- MUST populate the per-hop payloads as described in [BOLT 4](04-onion-routing.md#onion-messages).
- SHOULD retry via a different route if it expects a response and
doesn't receive one after a reasonable period.
+- SHOULD set `len` to 1366 or 32834.
The reader:
- MUST handle the per-hop payloads as described in [BOLT 4](04-onion-routing.md#onion-messages).
- SHOULD accept onion messages from peers without an established channel.
- MAY rate-limit messages by dropping them.
-## References
+## Rationale
+
+`len` allows larger messages to be sent than the standard 1300 bytes
+allowed for an HTLC onion, but this should be used sparingly as it is
+reduces anonymity set, hence the recommendation that it either look
+like an HTLC onion, or if larger, be a fixed size.
+
+
+# References
1. [RFC 1950 "ZLIB Compressed Data Format Specification version 3.3](https://www.ietf.org/rfc/rfc1950.txt)
2. [Maximum Compression Factor](https://zlib.net/zlib_tech.html)