Such holders allow you to display and fix the LEDs on the panel of any device or homemade. According to the seller, the holders are made of copper. The holders consist of several elements - a metal case with thread and a plastic "sleeve", in which, in fact, the LED is placed.
Dimensions of holders of 3 mm LEDs:
• body length: ~ 10 mm
• thread diameter: ~ 5 mm
• diameter of the output in the cone: ~ 6 mm
• diameter of the output in a plastic "sleeve": 3 mm
Dimensions of holders of 5 mm LEDs:
• body length: ~ 12 mm
• thread diameter: ~ 8 mm
• diameter of the output in the cone: ~ 9 mm
• diameter of the output in a plastic "sleeve": 5 mm
It should be noted that according to the statement of the seller himself, the size of finished products may differ from the stated size by 1-3 mm.
The link in the article leads to a lot with holders of 5 mm LEDs, holders for 3 mm LEDs (their price for September 2019 was ~ 90 rubles) you can purchase here. Both lots have 10 holders.
All in all, very good holders for a very small amount. The panel of the finished device with such holders looks aesthetically pleasing. The only drawback of such holders is that the LED in them sways slightly and when pressed goes into the case, but, for example, a drop of hot glue can solve this problem.
Cost: ~ 66