1Excellent Aluminium Alloy Material: This square hole drill bit adapter is made of excellent aluminium alloy material, which is sturdy and durable, with high hardness, not easy to be damaged, and has a long service life. 2Easy To Install:This square hole drill mounting bracket is easy to install and remove, you can quickly install or remove it by yourself, which is fast and convenient. 3Good Compatibility: This drill press mortising attachment is well adapted for mortising machines with a part width of around 20mm and an exposed part diameter of 3843mm. 4Efficient And Accurate: This square hole drill bit mortising attachment can make drilling very accurate and efficient, making the drilling smoother and more stable. 5Wide Application: This square hole drill fixing bracket has a wide range of applications and is perfect for woodworking and furniture making, ensuring accurate and sleek drilling. 1 xSquareHoleDrillBitAdapter 2 x Clamps 2 x Wrenches