1)Can you provide the customer with a detailed installation guide (step-by-step)? 2)After installation, what state of the product is considered qualified and what is not qualified? 3)I believe that the customer is also quite professional in plastic products. Can you have the customer compare this product with the previous one to determine if the toughness is insufficient or if their force is too great? 4)The merchant has used the same product status for testing and found no rupture. Can we send one of the merchant's products to the customer for them to install and test? The product has not undergone any modifications, including structure and materials.