This Print-Core-Holder I designed to get my cores on one place. You can screw it to your wall with suitable fixing screws.
Note for handle with it: You have to remove and insert the cores as you do it in your real core-holder in your Ultimaker 3. Press the 2 plastic noses together, put or pull it from or into the core holder until endposition.
Heating bead temperature 60°C.
Skirt with 4 lines