Adopt new ABS alloy material from Korea, high intensity, high toughness, not crack.
After the non-standard parts injection molded, it can keep the same size completely.
This avoid the error so that to improve the stability and accuracy of the printer and easy for assembly.
The bottom vertex has two different hole, one is 20*20, one is 15*20. You need to enter the profile from the side of 20*20, the hole 15*20 has a flange to avoid the profile come out.