Designed and printed them to secure things in my yard for recent hurricane. I used a big screw driver trough the top whole to get leverage and screw it down.

They need to be printed sturdy, so make sure the walls are at least 3mm thick and use high infill%.

I printed them using 0.8mm nozzle and 0.4mm layer height in PETG and 4 wall loops (that makes the walls almost 4mm thick). If using a smaller nozzle and strength is important increase the amount of wall loops. For me print time was a little over 2h. Note that you want to print them lying down so you get the strength of the layer lines along the length of the anchor, this means that some support is required.