diff --git a/tokio-postgres/src/tls.rs b/tokio-postgres/src/tls.rs
index bcb49778..d141d0d9 100644
--- a/tokio-postgres/src/tls.rs
+++ b/tokio-postgres/src/tls.rs
@@ -62,7 +62,7 @@ pub trait TlsStream: 'static + Sync + Send + AsyncRead + AsyncWrite {
     /// Returns the data associated with the `tls-unique` channel binding type as described in
     /// [RFC 5929], if supported.
     ///
-    /// An implementation only needs to support one of this or `tls_server_end_point`.
+    /// An implementation only needs to support at most one of this or `tls_server_end_point`.
     ///
     /// [RFC 5929]: https://tools.ietf.org/html/rfc5929
     fn tls_unique(&self) -> Option<Vec<u8>> {
@@ -72,7 +72,7 @@ pub trait TlsStream: 'static + Sync + Send + AsyncRead + AsyncWrite {
     /// Returns the data associated with the `tls-server-end-point` channel binding type as
     /// described in [RFC 5929], if supported.
     ///
-    /// An implementation only needs to support one of this or `tls_unique`.
+    /// An implementation only needs to support at most one of this or `tls_unique`.
     ///
     /// [RFC 5929]: https://tools.ietf.org/html/rfc5929
     fn tls_server_end_point(&self) -> Option<Vec<u8>> {