diff --git a/ip/iproute.c b/ip/iproute.c
index 52b06f5a..c144b740 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -57,7 +57,7 @@ static void usage(void)
 	fprintf(stderr, "NH := [ via ADDRESS ] [ dev STRING ] [ weight NUMBER ] NHFLAGS\n");
 	fprintf(stderr, "OPTIONS := FLAGS [ mtu NUMBER ] [ advmss NUMBER ]\n");
 	fprintf(stderr, "           [ rtt NUMBER ] [ rttvar NUMBER ]\n");
-	fprintf(stderr, "           [ window NUMBER] [ cwnd NUMBER ] [ ssthresh REALM ]\n");
+	fprintf(stderr, "           [ window NUMBER] [ cwnd NUMBER ] [ ssthresh NUMBER ]\n");
 	fprintf(stderr, "           [ realms REALM ]\n");
 	fprintf(stderr, "TYPE := [ unicast | local | broadcast | multicast | throw |\n");
 	fprintf(stderr, "          unreachable | prohibit | blackhole | nat ]\n");