diff --git a/zarrs/src/array/array_sync_sharded_readable_ext.rs b/zarrs/src/array/array_sync_sharded_readable_ext.rs
index cb97daf..c18f02f 100644
--- a/zarrs/src/array/array_sync_sharded_readable_ext.rs
+++ b/zarrs/src/array/array_sync_sharded_readable_ext.rs
@@ -88,7 +88,7 @@ impl ArrayShardedReadableExtCache {
 ///
 /// Sharding indexes are cached in a [`ArrayShardedReadableExtCache`] enabling faster retrieval.
 // TODO: Add default methods? Or change to options: Option<&CodecOptions>? Should really do this for array (breaking)...
-pub trait ArrayShardedReadableExt<TStorage: ?Sized + ReadableStorageTraits + 'static> {
+pub trait ArrayShardedReadableExt<TStorage: ?Sized + ReadableStorageTraits + 'static>: private::Sealed {
     /// Read and decode the inner chunk at `chunk_indices` into its bytes.
     ///
     /// See [`Array::retrieve_chunk_opt`].
@@ -472,6 +472,14 @@ impl<TStorage: ?Sized + ReadableStorageTraits + 'static> ArrayShardedReadableExt
     }
 }
 
+mod private {
+    use super::*;
+
+    pub trait Sealed {}
+
+    impl<TStorage: ?Sized + ReadableStorageTraits + 'static> Sealed for Array<TStorage> {}
+}
+
 #[cfg(test)]
 mod tests {
     use std::sync::Arc;