Khay Gridfinity giữ đầu Heat Insert Tip (đế ren 4mm)

These have a 4mm screw base.

You'll need to have your slicer set to exclusive slicing, and even then, you may have to run a 4mm drill bit through the holes, as they are a touch tight. The clearance for the knerled barrel is ok and fits nice and snug.

This is the link to the specific set used: https://www.temu.com/goods.html?_bg_fs=1&goods_id=601099601596036