diff --git a/.eslintrc b/.eslintrc
index 739c7ed..928d63a 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -16,6 +16,7 @@
 				"IteratorStep",
 				"IteratorValue",
 				"NormalCompletion",
+				"SetDataSize",
 				"ToBoolean",
 
 				// GetSetRecord
diff --git a/aos/SetDataSize.js b/aos/SetDataSize.js
new file mode 100644
index 0000000..a99e534
--- /dev/null
+++ b/aos/SetDataSize.js
@@ -0,0 +1,8 @@
+'use strict';
+
+var tools = require('es-set/tools');
+var $setSize = tools.size;
+
+module.exports = function SetDataSize(setData) {
+	return $setSize(setData);
+};
diff --git a/implementation.js b/implementation.js
index d5b72d6..d9f6ae8 100644
--- a/implementation.js
+++ b/implementation.js
@@ -11,6 +11,7 @@ var IteratorClose = require('es-abstract/2023/IteratorClose');
 var IteratorStep = require('es-abstract/2023/IteratorStep');
 var IteratorValue = require('es-abstract/2023/IteratorValue');
 var NormalCompletion = require('es-abstract/2023/NormalCompletion');
+var SetDataSize = require('./aos/SetDataSize');
 var ToBoolean = require('es-abstract/2023/ToBoolean');
 
 var isSet = require('is-set');
@@ -18,7 +19,7 @@ var isSet = require('is-set');
 var tools = require('es-set/tools');
 var $setForEach = tools.forEach;
 var $setHas = tools.has;
-var setSize = tools.size;
+var $setSize = tools.size;
 
 module.exports = function isDisjointFrom(other) {
 	var O = this; // step 1
@@ -30,7 +31,7 @@ module.exports = function isDisjointFrom(other) {
 
 	var otherRec = GetSetRecord(other); // step 3
 
-	var thisSize = setSize(O); // step 4
+	var thisSize = SetDataSize(O); // step 4
 
 	if (thisSize <= otherRec['[[Size]]']) { // step 5
 		try {
@@ -43,7 +44,7 @@ module.exports = function isDisjointFrom(other) {
 						// eslint-disable-next-line no-throw-literal
 						throw false; // step 5.b.iii.2, kinda
 					}
-					thisSize += setSize(O); // step 5.b.iii.4
+					thisSize += $setSize(O); // step 5.b.iii.4
 				}
 			});
 		} catch (e) {