More Product Model optimisation

app/Models/Supplier/Phone.php

@@ -2,24 +2,14 @@
 
 namespace App\Models\Supplier;
 
-use App\Interfaces\SupplierItem;
 use App\Models\Product\Phone as ProductVoip;
 
-final class Phone extends Type implements SupplierItem
+final class Phone extends Type
 {
-	protected const category_name = 'Telephone';
+	protected const category_name = 'Phone';
 
 	protected $table = 'supplier_phone';
 
-	/* INTERFACES */
-
-	public function getBillingIntervalAttribute(): int
-	{
-		return 1;	// Monthly
-	}
-
-	public function products()
-	{
-		return $this->hasMany(ProductVoip::class,'supplier_item_id','id');
-	}
+	// The model of the product that is supplied by this model
+	const ProductModel = ProductVoip::class;
 }