diff --git a/src/filter.rs b/src/filter.rs
index d49136c..f76f175 100644
--- a/src/filter.rs
+++ b/src/filter.rs
@@ -4,7 +4,7 @@
 ///
 
 /// The `Filter` trait is implemented by all the filters.
-pub trait Filter {
+pub trait Filter: Send {
     fn filter(&self) -> String;
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index ac8979c..638ef8d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -169,7 +169,7 @@ impl LdapClient {
         &mut self,
         base: &str,
         scope: Scope,
-        filter: &dyn Filter,
+        filter: &(impl Filter+?Sized),
         attributes: &Vec<&str>,
     ) -> Result<SearchEntry, Error> {
         let search = self
@@ -310,7 +310,7 @@ impl LdapClient {
         &mut self,
         base: &str,
         scope: Scope,
-        filter: &dyn Filter,
+        filter: &impl Filter,
         attributes: &Vec<&str>,
     ) -> Result<T, Error> {
         let search_entry = self.search_innter(base, scope, filter, attributes).await?;