Self Tapping Insert with Cutting Bores 307 Bore Type Thread Insert is a new kind of fastener that strengthens the thread strength. Threaded Hole Insert 307 Self Tapping has the characteristics of “self-tapping”. 307 Type Self-Tapping Thread Insert does not need to use the tap to machine the bottom hole thread. It only needs to pre-drill the bottom hole and then directly install it with the installation tool. Into, high installation efficiency, embedded in plastic, aluminum alloy, cast iron, copper and other soft materials, can form a higher strength internal thread hole. Size& Type: Metric: M2-M30, with cutting slot, also for normal Inch sizes. M3-M24, with cutting bore, also for normal Inch sizes. Material: Stainless Steel Case-hardened steel, zinc plated Brass Other material on request Finishes & Coating: Zinc plated (Yellow, Blue, etc.) Dry Film Lubricants