These are some additions I made to @3DPRINTINGWORLD 's awesome lightsaber. I love to cosplay and needed these items to complete the saber for a prop I so I can wear it at a con.
The end cap is the same as his, but two holes have been added. One for the Key Ring and one as an air hole. I find the blades extend much better if there is an air inlet to relieve air pressure.
The Key Ring has a slight break in one side so you can slide it in the hole. Then superglue the two ends.
The cap has a thumb tab to help you get the cap off and inside the cap are small tabs that latch to hold the cap on. This was necessary addition to keep the blade in the hilt while wearing the saber on your belt. I printed it at 100% and had no trouble popping it on and off. Depending on how you printed your saber, you may have to increase/decrease the size in your slicer.
I printed the entire saber at 0.1 layer height and so I did the same with these. In Cura 4.1, I just used the preset "Fine" (with adjustments for calibration to retraction and flow).