diff --git a/apps/ts.c b/apps/ts.c
index 924108f..eda5297 100644
--- a/apps/ts.c
+++ b/apps/ts.c
@@ -107,7 +107,7 @@
     {"queryfile", OPT_QUERYFILE, '<', "File containing a TS query"},
     {"passin", OPT_PASSIN, 's', "Input file pass phrase source"},
     {"inkey", OPT_INKEY, '<', "File with private key for reply"},
-    {"signer", OPT_SIGNER, 's'},
+    {"signer", OPT_SIGNER, 's', "Signer certificate file"},
     {"chain", OPT_CHAIN, '<', "File with signer CA chain"},
     {"verify", OPT_VERIFY, '-', "Verify a TS response"},
     {"CApath", OPT_CAPATH, '/', "Path to trusted CA files"},