diff --git a/lib/support/cli.js b/lib/support/cli.js
index 7ecf2c1c5..a89c8d146 100644
--- a/lib/support/cli.js
+++ b/lib/support/cli.js
@@ -187,11 +187,11 @@ module.exports.parseCommandLine = function parseCommandLine() {
     })
     .option('browsertime.requestheader', {
       alias: 'r',
-      describe: 'Request header that will be added to the request. Add multiple instances to add multiple request headers',
+      describe: 'Request header that will be added to the request. Add multiple instances to add multiple request headers. Only Chrome support for now.',
       group: 'Browser'
     })
     .option('browsertime.block', {
-      describe: 'Domain to block. Add multiple instances to add multiple domains that will be blocked.',
+      describe: 'Domain to block. Add multiple instances to add multiple domains that will be blocked. Only Chrome support for now.',
       group: 'Browser'
     })
     .option('browsertime.proxy.http', {