diff --git a/index.js b/index.js
index 9725aad..ac2db1c 100644
--- a/index.js
+++ b/index.js
@@ -51,7 +51,7 @@ class Channel {
   }
 
   async open(handshake) {
-    if (this._slave) {
+    if (this._mux._slave) {
       await this._mux.pullLocal();
       await this._mux.pullFree();
     }
@@ -65,7 +65,7 @@ class Channel {
     this._localId = id + 1;
     this._mux._local[id] = this;
 
-    if (this._slave) {
+    if (this._mux._slave) {
       if (freeLen > 0) {
         await this._mux.popFree(id);
       } else {
@@ -153,14 +153,14 @@ class Channel {
     if (this._remoteId > 0) {
       this._mux._remote[this._remoteId - 1] = null;
       this._remoteId = 0;
-      if (this._slave) {
+      if (this._mux._slave) {
         await this._mux.pullFree();
       }
       // If remote has acked, we can reuse the local id now
       // otherwise, we need to wait for the "ack" to arrive
       this._mux._free.push(this._localId - 1);
 
-      if (this._slave) {
+      if (this._mux._slave) {
         await this._mux.pushFree(this._localId - 1);
       }
     }