diff --git a/README.md b/README.md
index 5ceae42..484c1b7 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,8 @@ validates :iban, iban: { tags: [:sepa] }
  => "IL317532867920826062774"
 ```
 
+Note: It can't generate a valid IBAN code for some countries where iban check digits are fixed if validation code for that country is not available.
+
 ## Installation
 
 1. Add this line to your application's Gemfile
diff --git a/spec/iban_bic/random_spec.rb b/spec/iban_bic/random_spec.rb
index fe2577e..293c974 100644
--- a/spec/iban_bic/random_spec.rb
+++ b/spec/iban_bic/random_spec.rb
@@ -37,14 +37,14 @@
     end
 
     context "when not_tags are given" do
-      let(:params) { { not_tags: [:sepa] } }
+      let(:params) { { not_tags: [:fixed_iban_check] } }
 
       it "returns a valid IBAN" do
         expect(IbanBic.valid?(subject)).to be_truthy
       end
 
       it "returns a valid IBAN from a country without that tags" do
-        expect(IbanBic.has_tags?(subject, [:sepa])).to be_falsey
+        expect(IbanBic.has_tags?(subject, [:fixed_iban_check])).to be_falsey
       end
     end
   end