diff --git a/src/transaction/Details.tsx b/src/transaction/Details.tsx
index 23f463a..bfd8747 100644
--- a/src/transaction/Details.tsx
+++ b/src/transaction/Details.tsx
@@ -70,10 +70,10 @@ const Details: React.FC<DetailsProps> = ({
   const fourBytes = rawInputTo4Bytes(txData.data);
   const fourBytesEntry = use4Bytes(fourBytes);
   const fourBytesTxDesc = useMemo(() => {
-    if (!txData || !fourBytesEntry?.signatureWithoutParamNames) {
+    if (!txData || !fourBytesEntry?.signature) {
       return undefined;
     }
-    const sig = fourBytesEntry?.signatureWithoutParamNames;
+    const sig = fourBytesEntry?.signature;
     const functionFragment = Fragment.fromString(`function ${sig}`);
     const intf = new Interface([functionFragment]);
     return intf.parseTransaction({ data: txData.data, value: txData.value });
diff --git a/src/transaction/decoder/DecodedParamsTable.tsx b/src/transaction/decoder/DecodedParamsTable.tsx
index 6f550f4..636dd67 100644
--- a/src/transaction/decoder/DecodedParamsTable.tsx
+++ b/src/transaction/decoder/DecodedParamsTable.tsx
@@ -28,7 +28,9 @@ const DecodedParamsTable: React.FC<DecodedParamsTableProps> = ({
       {!hasParamNames && (
         <tr className="grid grid-cols-12 text-left gap-x-2 py-2 bg-yellow-100 text-red-700">
           <th className="col-span-12 px-1">
-            Parameter names are not available.
+            {paramTypes.length > 0 && paramTypes[0].name !== null
+              ? "Parameter names are estimated."
+              : "Parameter names are not available."}
           </th>
         </tr>
       )}
diff --git a/src/use4Bytes.ts b/src/use4Bytes.ts
index 622f327..9fe9252 100644
--- a/src/use4Bytes.ts
+++ b/src/use4Bytes.ts
@@ -4,14 +4,12 @@ import { fourBytesURL } from "./url";
 
 export type FourBytesEntry = {
   name: string;
-  signatureWithoutParamNames: string | undefined;
-  signatures: string[] | undefined;
+  signature: string | undefined;
 };
 
 const simpleTransfer: FourBytesEntry = {
   name: "Transfer",
-  signatureWithoutParamNames: undefined,
-  signatures: undefined,
+  signature: undefined,
 };
 
 const fullCache = new Map<string, FourBytesEntry | null>();
@@ -68,8 +66,7 @@ export const use4Bytes = (
 
         const entry: FourBytesEntry = {
           name: method,
-          signatureWithoutParamNames: sig,
-          signatures: undefined,
+          signature: sig,
         };
         setEntry(entry);
         fullCache.set(fourBytes, entry);