diff --git a/acme.sh b/acme.sh
index 9b33fc74..dae42714 100755
--- a/acme.sh
+++ b/acme.sh
@@ -6212,7 +6212,7 @@ Parameters:
   --dnssleep  [$DEFAULT_DNS_SLEEP]                  The time in seconds to wait for all the txt records to take effect in dns api mode. Default $DEFAULT_DNS_SLEEP seconds.
 
   --keylength, -k [2048]            Specifies the domain key length: 2048, 3072, 4096, 8192 or ec-256, ec-384, ec-521.
-  --accountkeylength, -ak [2048]    Specifies the account key length.
+  --accountkeylength, -ak [2048]    Specifies the account key length: 2048, 3072, 4096
   --log    [/path/to/logfile]       Specifies the log file. The default is: \"$DEFAULT_LOG_FILE\" if you don't give a file path here.
   --log-level 1|2                   Specifies the log level, default is 1.
   --syslog [0|3|6|7]                Syslog level, 0: disable syslog, 3: error, 6: info, 7: debug.