Qjaiune 5Pcs 1/4" to 1/8" Collet Chuck Driver Adapter, CNC Engraving Bit Router Adapter Convert for Engraving Machine Tool - - Amazon.com
Bioristar 1/4 to 1/8 Collet Adapter Router CNC Engraving Bit Router Adapter Convert Pack of 6 (6.35mm to3.175mm)) - - Amazon.com
uxcell Router Collet Driver Adapter Set Convert 8mm/12mm/12.7mm to 6mm 8mm/9.5mm/12.5mm to 6.35mm 10mm/12mm to 8mm 12mm to 10mm for CNC Engraving Bit Machine - - Amazon.com
ZOTOP Shank Router Collet Extension Chuck Holder Extender Router Adapter Milling Bits with ER20 Spring Collet Convert 1/2-inch & 1/4-inch Shank Bits ER20 M Type Collet Chuck Wrench Spanner - - Amazon.com
4 pc Collet Reducer Bushing for 8mm, 1/4" Router Bit - - Amazon.com
1/2" to 1/4" Router Bit Collet Extension and Reducer. Extends The Router Bit an Additional 2-1/4" and Accepts 1/4" Shank Router Bits Into the Collet - - Amazon.com
szzijia CNC Engraving Bit Router Adapter Convert 1/4" to 1/8" for Engraving Machine Tool (Pack of 5): Amazon.com: Tools & Home Improvement
Die Grinder Router 1/4 to 1/8-inch Adapter Chuck Collet - - Amazon.com