diff --git a/b2/CHAR b/b2/CHAR
index a1126bd..4e3a66c 100644
--- a/b2/CHAR
+++ b/b2/CHAR
@@ -1,2 +1,2 @@
-FOO R101X	FP=0603 R=100R TOL=5x
-FOO R102Y	FP=0603 R=1k TOL=1x
+FOO R101X	FP=0603 R=100R TOL=5%
+FOO R102Y	FP=0603 R=1k TOL=1%
diff --git a/b2/lang.l b/b2/lang.l
index be252dd..c2b9744 100644
--- a/b2/lang.l
+++ b/b2/lang.l
@@ -46,6 +46,14 @@ void parse_characteristics(void)
 
 %}
 
+
+/*
+ * We use ID for a bit of a hack: let %... be recognized as '%' WORD but treat
+ * ...% still as a single WORD.
+ */
+
+ID	[-_A-Za-z0-9()+./]
+
 %%
 
 %{
@@ -57,7 +65,7 @@ void parse_characteristics(void)
 	}
 %}
 
-[-_A-Za-z0-9()+./]+		{ yylval.s = unique(yytext);
+{ID}({ID}|"%")*			{ yylval.s = unique(yytext);
 				  return WORD; }
 
 "<="				return TOK_LE;