diff --git a/src/Model/Entity/ExternalProductCatalogsProductCatalog.php b/src/Model/Entity/ExternalProductCatalogsProductCatalog.php
new file mode 100644
index 0000000..0357b32
--- /dev/null
+++ b/src/Model/Entity/ExternalProductCatalogsProductCatalog.php
@@ -0,0 +1,40 @@
+<?php
+declare(strict_types=1);
+
+namespace CakeProducts\Model\Entity;
+
+use Cake\I18n\DateTime;
+use Cake\ORM\Entity;
+
+/**
+ * ExternalProductCatalogsProductCatalog Entity
+ *
+ * @property int $id
+ * @property string $external_product_catalog_id
+ * @property string $product_catalog_id
+ * @property DateTime $created
+ * @property bool $enabled
+ *
+ * @property ExternalProductCatalog $external_product_catalog
+ * @property ProductCatalog $product_catalog
+ */
+class ExternalProductCatalogsProductCatalog extends Entity
+{
+    /**
+     * Fields that can be mass assigned using newEntity() or patchEntity().
+     *
+     * Note that when '*' is set to true, this allows all unspecified fields to
+     * be mass assigned. For security purposes, it is advised to set '*' to false
+     * (or remove it), and explicitly make individual fields accessible as needed.
+     *
+     * @var array<string, bool>
+     */
+    protected array $_accessible = [
+        'external_product_catalog_id' => true,
+        'product_catalog_id' => true,
+        'created' => true,
+        'enabled' => true,
+        'external_product_catalog' => true,
+        'product_catalog' => true,
+    ];
+}
diff --git a/src/Model/Table/ExternalProductCatalogsProductCatalogsTable.php b/src/Model/Table/ExternalProductCatalogsProductCatalogsTable.php
new file mode 100644
index 0000000..a6d3325
--- /dev/null
+++ b/src/Model/Table/ExternalProductCatalogsProductCatalogsTable.php
@@ -0,0 +1,107 @@
+<?php
+declare(strict_types=1);
+
+namespace CakeProducts\Model\Table;
+
+use Cake\Datasource\EntityInterface;
+use Cake\Datasource\ResultSetInterface;
+use Cake\ORM\Association\BelongsTo;
+use Cake\ORM\Behavior\TimestampBehavior;
+use Cake\ORM\Query\SelectQuery;
+use Cake\ORM\RulesChecker;
+use Cake\ORM\Table;
+use Cake\Validation\Validator;
+use CakeProducts\Model\Entity\ExternalProductCatalogsProductCatalog;
+use Closure;
+use Psr\SimpleCache\CacheInterface;
+
+/**
+ * ExternalProductCatalogsProductCatalogs Model
+ *
+ * @property ExternalProductCatalogsTable&BelongsTo $ExternalProductCatalogs
+ * @property ProductCatalogsTable&BelongsTo $ProductCatalogs
+ *
+ * @method ExternalProductCatalogsProductCatalog newEmptyEntity()
+ * @method ExternalProductCatalogsProductCatalog newEntity(array $data, array $options = [])
+ * @method array<ExternalProductCatalogsProductCatalog> newEntities(array $data, array $options = [])
+ * @method ExternalProductCatalogsProductCatalog get(mixed $primaryKey, array|string $finder = 'all', CacheInterface|string|null $cache = null, Closure|string|null $cacheKey = null, mixed ...$args)
+ * @method ExternalProductCatalogsProductCatalog findOrCreate($search, ?callable $callback = null, array $options = [])
+ * @method ExternalProductCatalogsProductCatalog patchEntity(EntityInterface $entity, array $data, array $options = [])
+ * @method array<ExternalProductCatalogsProductCatalog> patchEntities(iterable $entities, array $data, array $options = [])
+ * @method ExternalProductCatalogsProductCatalog|false save(EntityInterface $entity, array $options = [])
+ * @method ExternalProductCatalogsProductCatalog saveOrFail(EntityInterface $entity, array $options = [])
+ * @method iterable<ExternalProductCatalogsProductCatalog>|ResultSetInterface<ExternalProductCatalogsProductCatalog>|false saveMany(iterable $entities, array $options = [])
+ * @method iterable<ExternalProductCatalogsProductCatalog>|ResultSetInterface<ExternalProductCatalogsProductCatalog> saveManyOrFail(iterable $entities, array $options = [])
+ * @method iterable<ExternalProductCatalogsProductCatalog>|ResultSetInterface<ExternalProductCatalogsProductCatalog>|false deleteMany(iterable $entities, array $options = [])
+ * @method iterable<ExternalProductCatalogsProductCatalog>|ResultSetInterface<ExternalProductCatalogsProductCatalog> deleteManyOrFail(iterable $entities, array $options = [])
+ *
+ * @mixin TimestampBehavior
+ */
+class ExternalProductCatalogsProductCatalogsTable extends Table
+{
+    /**
+     * Initialize method
+     *
+     * @param array<string, mixed> $config The configuration for the Table.
+     * @return void
+     */
+    public function initialize(array $config): void
+    {
+        parent::initialize($config);
+
+        $this->setTable('external_product_catalogs_product_catalogs');
+        $this->setDisplayField('external_product_catalog_id');
+        $this->setPrimaryKey('id');
+
+        $this->addBehavior('Timestamp');
+
+        $this->belongsTo('ExternalProductCatalogs', [
+            'foreignKey' => 'external_product_catalog_id',
+            'joinType' => 'INNER',
+        ]);
+        $this->belongsTo('ProductCatalogs', [
+            'foreignKey' => 'product_catalog_id',
+            'joinType' => 'INNER',
+        ]);
+    }
+
+    /**
+     * Default validation rules.
+     *
+     * @param Validator $validator Validator instance.
+     * @return Validator
+     */
+    public function validationDefault(Validator $validator): Validator
+    {
+        $validator
+            ->scalar('external_product_catalog_id')
+            ->maxLength('external_product_catalog_id', 255)
+            ->notEmptyString('external_product_catalog_id');
+
+        $validator
+            ->uuid('product_catalog_id')
+            ->notEmptyString('product_catalog_id');
+
+        $validator
+            ->boolean('enabled')
+            ->requirePresence('enabled', 'create')
+            ->notEmptyString('enabled');
+
+        return $validator;
+    }
+
+    /**
+     * Returns a rules checker object that will be used for validating
+     * application integrity.
+     *
+     * @param RulesChecker $rules The rules object to be modified.
+     * @return RulesChecker
+     */
+    public function buildRules(RulesChecker $rules): RulesChecker
+    {
+        $rules->add($rules->existsIn(['external_product_catalog_id'], 'ExternalProductCatalogs'), ['errorField' => 'external_product_catalog_id']);
+        $rules->add($rules->existsIn(['product_catalog_id'], 'ProductCatalogs'), ['errorField' => 'product_catalog_id']);
+
+        return $rules;
+    }
+}
diff --git a/webroot/js/product_catalogs.js b/webroot/js/product_catalogs.js
new file mode 100644
index 0000000..05a1587
--- /dev/null
+++ b/webroot/js/product_catalogs.js
@@ -0,0 +1,16 @@
+const addProductCatalogButton = document.getElementById('add-product-catalog-button');
+const productCatalogsPrefixInput = document.getElementById('catalog_prefix');
+if (addProductCatalogButton && productCatalogsPrefixInput) {
+    addProductCatalogButton.addEventListener('click', addProductCatalogButtonClicked);
+}
+function addProductCatalogButtonClicked(e)
+{
+    e.preventDefault();
+    console.debug('productCatalogsPrefixInput.value');
+    console.debug(productCatalogsPrefixInput.value);
+    productCatalogsPrefixInput.value = parseInt(productCatalogsPrefixInput.value) + 1;
+    productCatalogsPrefixInput.dispatchEvent(new Event('change'));
+    console.debug('productCatalogsPrefixInput.value');
+    console.debug(productCatalogsPrefixInput.value);
+
+}