diff --git a/ts_src/transaction.ts b/ts_src/transaction.ts
index 218d004..37b88f5 100644
--- a/ts_src/transaction.ts
+++ b/ts_src/transaction.ts
@@ -36,18 +36,13 @@ const ONE: Buffer = Buffer.from(
   'hex',
 );
 const VALUE_UINT64_MAX: Buffer = Buffer.from('ffffffffffffffff', 'hex');
-const BLANK_OUTPUT: BlankOutput = {
+const BLANK_OUTPUT = {
   script: EMPTY_SCRIPT,
   valueBuffer: VALUE_UINT64_MAX,
 };
 
-function isOutput(out: Output | BlankOutput): out is Output {
-  return (out as Output).value !== undefined;
-}
-
-export interface BlankOutput {
-  script: Buffer;
-  valueBuffer: Buffer;
+function isOutput(out: Output): boolean {
+  return out.value !== undefined;
 }
 
 export interface Output {
@@ -55,8 +50,6 @@ export interface Output {
   value: number;
 }
 
-type OpenOutput = Output | BlankOutput;
-
 export interface Input {
   hash: Buffer;
   index: number;
@@ -185,7 +178,7 @@ export class Transaction {
   version: number = 1;
   locktime: number = 0;
   ins: Input[] = [];
-  outs: OpenOutput[] = [];
+  outs: Output[] = [];
 
   isCoinbase(): boolean {
     return (
@@ -333,7 +326,7 @@ export class Transaction {
 
       // "blank" outputs before
       for (let i = 0; i < inIndex; i++) {
-        txTmp.outs[i] = BLANK_OUTPUT;
+        (txTmp.outs as any)[i] = BLANK_OUTPUT;
       }
 
       // ignore sequence numbers (except at inIndex)
@@ -602,7 +595,7 @@ export class Transaction {
       if (isOutput(txOut)) {
         writeUInt64(txOut.value);
       } else {
-        writeSlice(txOut.valueBuffer);
+        writeSlice((txOut as any).valueBuffer);
       }
 
       writeVarSlice(txOut.script);
diff --git a/types/transaction.d.ts b/types/transaction.d.ts
index d7462b4..f0db04e 100644
--- a/types/transaction.d.ts
+++ b/types/transaction.d.ts
@@ -1,12 +1,7 @@
-export interface BlankOutput {
-    script: Buffer;
-    valueBuffer: Buffer;
-}
 export interface Output {
     script: Buffer;
     value: number;
 }
-declare type OpenOutput = Output | BlankOutput;
 export interface Input {
     hash: Buffer;
     index: number;
@@ -28,7 +23,7 @@ export declare class Transaction {
     version: number;
     locktime: number;
     ins: Input[];
-    outs: OpenOutput[];
+    outs: Output[];
     isCoinbase(): boolean;
     addInput(hash: Buffer, index: number, sequence?: number, scriptSig?: Buffer): number;
     addOutput(scriptPubKey: Buffer, value: number): number;
@@ -56,4 +51,3 @@ export declare class Transaction {
     private __byteLength;
     private __toBuffer;
 }
-export {};