The Thread Repair Kit M16 x 2D with Replacement Inserts (5pcs) is a set designed to repair or restore damaged threads in M16-sized holes. The "M16" refers to the metric thread size (16mm in diameter), and "2D" likely indicates the pitch or thread design. This kit includes five replacement inserts, which are used to restore the original thread profile, making it possible to reuse the damaged holes. The inserts are typically made of durable materials like steel or brass, providing a strong, long-lasting repair. Ideal for automotive, mechanical, or industrial applications, this kit helps to extend the life of bolts and threaded components.