diff --git a/saturated_int--0.0.1.sql b/saturated_int--0.0.1.sql
index 422eb75..58a0e8f 100644
--- a/saturated_int--0.0.1.sql
+++ b/saturated_int--0.0.1.sql
@@ -8,11 +8,21 @@ RETURNS cstring
 AS 'int4out'
 LANGUAGE internal IMMUTABLE STRICT PARALLEL SAFE;
 
+CREATE FUNCTION sat_int4_recv(internal)
+RETURNS saturated_int
+AS 'int4recv'
+LANGUAGE internal IMMUTABLE PARALLEL SAFE;
+
+CREATE FUNCTION sat_int4_send(saturated_int)
+RETURNS bytea
+AS 'int4send'
+LANGUAGE internal IMMUTABLE PARALLEL SAFE;
+
 CREATE TYPE saturated_int (
     input = sat_int4_in,
     output = sat_int4_out,
-    -- receive = ...,
-    -- send = ...,
+    receive = sat_int4_recv,
+    send = sat_int4_send,
     like = integer,
     category = 'N'
 );
diff --git a/test/expected/002_saturated_int_agg.out b/test/expected/002_saturated_int_agg.out
new file mode 100644
index 0000000..2b2810d
--- /dev/null
+++ b/test/expected/002_saturated_int_agg.out
@@ -0,0 +1,21 @@
+CREATE TABLE sat_agg (id1 saturated_int, id2 saturated_int);
+INSERT INTO sat_agg
+SELECT i, 1 FROM pg_catalog.generate_series(2147483645::bigint, 2147483650::bigint) g(i);
+SELECT * FROM sat_agg;
+    id1     | id2 
+------------+-----
+ 2147483645 | 1
+ 2147483646 | 1
+ 2147483647 | 1
+ 2147483647 | 1
+ 2147483647 | 1
+ 2147483647 | 1
+(6 rows)
+
+-- Test aggregate functions
+SELECT sum(id1), sum(id2) FROM sat_agg;
+    sum     | sum 
+------------+-----
+ 2147483647 | 6
+(1 row)
+
diff --git a/test/sql/002_saturated_int_agg.sql b/test/sql/002_saturated_int_agg.sql
new file mode 100644
index 0000000..e38e424
--- /dev/null
+++ b/test/sql/002_saturated_int_agg.sql
@@ -0,0 +1,9 @@
+CREATE TABLE sat_agg (id1 saturated_int, id2 saturated_int);
+
+INSERT INTO sat_agg
+SELECT i, 1 FROM pg_catalog.generate_series(2147483645::bigint, 2147483650::bigint) g(i);
+
+SELECT * FROM sat_agg;
+
+-- Test aggregate functions
+SELECT sum(id1), sum(id2) FROM sat_agg;