diff --git a/yandexmarket/products.proto b/yandexmarket/products.proto
index 0d38fae..1003ee0 100644
--- a/yandexmarket/products.proto
+++ b/yandexmarket/products.proto
@@ -9,7 +9,7 @@ service ProductsService {
 
 message CalculateProductTariffsRequest {
 
-  message Offers {
+  message Offer {
     int64 category_id = 1;
     int64 price = 2;
     int64 length = 3;
@@ -19,7 +19,7 @@ message CalculateProductTariffsRequest {
     int64 quantity = 7;
   }
 
-  message Parameters {
+  message Parameter {
     int64 campaign_id = 1;
     string selling_program = 2;
     string frequency = 3;
@@ -27,8 +27,8 @@ message CalculateProductTariffsRequest {
   }
 
   int64 marketplace_id = 1;
-  Parameters parameters = 2;
-  repeated Offers offers = 3;
+  Parameter parameters = 2;
+  repeated Offer offers = 3;
 }
 
 message CalculateProductTariffsResponse {