broken product; faulty product
Refers to a product that is broken or defective, often in the context of returns, repairs, or second-hand sales.
Can I return this broken product?
I sent the faulty product for repair.
中古品 means a second-hand or used item, which may or may not be faulty; 故障品 specifically indicates a broken or defective condition.
Compound of 故障 (koshō, 'breakdown, failure') and 品 (hin, 'product, goods').