--- a/devtools/client/netmonitor/src/reducers/ui.js
+++ b/devtools/client/netmonitor/src/reducers/ui.js
@@ -32,18 +32,18 @@ const cols = {
   protocol: false,
   scheme: false,
   domain: true,
   remoteip: false,
   cause: true,
   type: true,
   cookies: false,
   setCookies: false,
-  transferred: true,
-  contentSize: false,
+  transferred: false,
+  contentSize: true,
   startTime: false,
   endTime: false,
   responseTime: false,
   duration: false,
   latency: false,
   waterfall: true,
 };
 const Columns = I.Record(

--- a/devtools/client/preferences/devtools.js
+++ b/devtools/client/preferences/devtools.js
@@ -156,17 +156,17 @@ pref("devtools.serviceWorkers.testing.en
 pref("devtools.netmonitor.enabled", true);
 
 // The default Network Monitor UI settings
 pref("devtools.netmonitor.panes-network-details-width", 550);
 pref("devtools.netmonitor.panes-network-details-height", 450);
 pref("devtools.netmonitor.filters", "[\"all\"]");
 pref("devtools.netmonitor.visibleColumns",
   // "[\"status\",\"method\",\"file\",\"domain\",\"cause\",\"type\",\"transferred\",\"contentSize\",\"waterfall\"]"
-  "[\"status\",\"method\",\"file\",\"domain\",\"cause\",\"type\",\"transferred\",\"waterfall\"]"
+  "[\"status\",\"method\",\"file\",\"domain\",\"cause\",\"type\",\"contentSize\",\"waterfall\"]"
   // "[\"status\",\"file\",\"cause\",\"type\",\"transferred\",\"waterfall\"]"
 );
 
 // The default Network monitor HAR export setting
 pref("devtools.netmonitor.har.defaultLogDir", "");
 pref("devtools.netmonitor.har.defaultFileName", "Archive %date");
 pref("devtools.netmonitor.har.jsonp", false);
 pref("devtools.netmonitor.har.jsonpCallback", "");