ITEM NAME:1/4" shank bits Router Collet Extension Engraving machine extension rod Description: - High precision, stable performance. - High strength and hardness. - Durable and practical to use. - Make you more efficient to process products. - Suitable for automobile manufacturing, mold manufacturing, machinery manufacturing and so on. Specification: - Material: Hardened Alloy Steel - Overall Length: approx.76mm/ 3inch - Internal Diameter of Connector: approx.6.35mm/ 0.25inch - External Diameter of Connector: approx.21.8mm/ 0.85inch - Bore Diameter: approx.6.35mm/ 0.25inch - Color: black as shown in the display pictures Package Included: 1 Piece Extension Rod.1 Piece Extension Rod. - High strength and hardness. - Make you more efficient to process products. - Color: black as shown in the display pictures.