diff --git a/actix-server/src/ssl/nativetls.rs b/actix-server/src/ssl/nativetls.rs
index 22d4bc56..62b8f4c7 100644
--- a/actix-server/src/ssl/nativetls.rs
+++ b/actix-server/src/ssl/nativetls.rs
@@ -13,7 +13,7 @@ use crate::{Io, Protocol, ServerConfig};
 /// Support `SSL` connections via native-tls package
 ///
 /// `tls` feature enables `NativeTlsAcceptor` type
-pub struct NativeTlsAcceptor<T, P> {
+pub struct NativeTlsAcceptor<T, P = ()> {
     acceptor: TlsAcceptor,
     io: PhantomData<(T, P)>,
 }
diff --git a/actix-server/src/ssl/openssl.rs b/actix-server/src/ssl/openssl.rs
index 62141be5..23ec1531 100644
--- a/actix-server/src/ssl/openssl.rs
+++ b/actix-server/src/ssl/openssl.rs
@@ -13,7 +13,7 @@ use crate::{Io, Protocol, ServerConfig};
 /// Support `SSL` connections via openssl package
 ///
 /// `ssl` feature enables `OpensslAcceptor` type
-pub struct OpensslAcceptor<T, P> {
+pub struct OpensslAcceptor<T, P = ()> {
     acceptor: SslAcceptor,
     io: PhantomData<(T, P)>,
 }
diff --git a/actix-server/src/ssl/rustls.rs b/actix-server/src/ssl/rustls.rs
index bd85ffe5..11bca355 100644
--- a/actix-server/src/ssl/rustls.rs
+++ b/actix-server/src/ssl/rustls.rs
@@ -15,7 +15,7 @@ use crate::{Io, Protocol, ServerConfig as SrvConfig};
 /// Support `SSL` connections via rustls package
 ///
 /// `rust-tls` feature enables `RustlsAcceptor` type
-pub struct RustlsAcceptor<T, P> {
+pub struct RustlsAcceptor<T, P = ()> {
     config: Arc<ServerConfig>,
     io: PhantomData<(T, P)>,
 }