What's in the box:

Spring Steel 8mm Shank Router Bit Extension Rod Milling Cutter Extender Collet Holder Adapter with ER16-8 8mm Collet Chuck (Type 2)

Features:
Router bit extension rod + collet chuck kit for woodworking trimming, milling, engraving machine.
Made of high-quality spring steel material, durable and sturdy.
The extension rod can eliminate the dangerous of withdrawing the shank from the collet.
And extending the router bit to provide the full depth of cut.
Make you work better, safer, more efficient and more labor saving.

Specifications:
Shank Diameter: 1/4 inch, 8mm, 1/2 inch(optional)
Material: Spring Steel
Item size: 6.35 * 22 * 88mm(1/4 inch), 8 * 22 * 88mm(8mm), 12.7 * 28 * 88mm(1/2 inch)
Item Weight: 90g(1/4 inch), 97g(8mm), 150g(1/2 inch)

Package List:
1 * Router Bit Extender
1 * Collet Chuck