After moving or re-configuring my OMAR shelving, I'm often missing these little bumper caps that seal the ends to avoid damaging anything you drag across the top shelves. They are small and not every arrangement of the shelves uses all of them, so they tend to get misplaced. They also tend to crack if heavy objects are placed on them. I designed a replacement piece that's optimized for 3D printing. 

It works with OMAR shelves, such as 100.697.63 and 000.697.68. Example here: https://www.ikea.com/us/en/p/omar-shelf-unit-galvanized-10069763/

The IKEA component number for the end cap is 139285 10055957, but IKEA does not offer this part for individual sale—and, if they did, the shipping would cost far more than the part.

Printing Notes:
• Any sturdy plastic (such as PETG).
• No supports needed.
• Brim not needed. 
• Infill ≥ 15%.

Assembly: 
• With the round end up, push the plug into the steel tubing on to of the shelf.
• Don't worry if the flat rings on the model bend inside the tubing; they are only there to stabilize it and provide friction. A perfect fit is not needed.
• The caps should remain in place unless pried out again.

Today I Learned: 
In addition to being a popular name, Omar is a brand of candy from Finland.
https://en.wikipedia.org/wiki/Omar_(candy)