diff --git a/backend/src/utils/validation.js b/backend/src/utils/validation.js
index fafede7..77a9e60 100644
--- a/backend/src/utils/validation.js
+++ b/backend/src/utils/validation.js
@@ -94,9 +94,12 @@ const userProductSchema = Joi.object({
       id: Joi.number().optional(), // For existing settings
       equipmentId: Joi.number().integer().positive().optional(), // Link to user_equipment
       // Equipment details (for display purposes)
-      equipmentName: Joi.string().max(255).optional(),
-      equipmentManufacturer: Joi.string().max(100).optional(),
-      equipmentModel: Joi.string().max(100).optional(),
+      equipmentName: Joi.string().max(255).allow(null, '').optional(),
+      equipmentManufacturer: Joi.string().max(100).allow(null, '').optional(),
+      equipmentModel: Joi.alternatives().try(
+        Joi.string().max(100).allow(''),
+        Joi.allow(null)
+      ).optional(),
       // Legacy fields for backward compatibility
       spreaderBrand: Joi.string().max(100).allow(null, '').optional(),
       spreaderModel: Joi.alternatives().try(