Extra Long Elbow-Plug Pair for CISS (Continuous Ink Supply Systems).
Includes 4x Extra Long Elbows (Plastic & Steel)  and 4x Plugs.  The steel head is for easier insert into sponges.
Use with 1.4 - 1.8 mm ID tubing (desktop printers)
The end is made of very sharp stainless steel which made it easier to install into sponge cartridges

4x Elbows and 4x Sleeves for Desktop Printers. 

Sleeve:

• OD: 4 mm (after elbow insert: 4.5 mm)
• ID: 2mm 
• Length: 6 mm

Elbow:

• Sleeve connection(straight):
  • OD: 2.6 mm
  • ID: 1.4 mm
  • Length: 
    • Plastic length: 8.5 mm
    • Steel length:  13.5 mm with tip
    • Total: 21.5 mm with tip, 18 mm without tip
• Tube connection (gradual)
  • OD: 1.8 to 2.2 mm
  • ID: 1.0 mm
  • Length: 5.5 mm

The air bubble has been a problem for Continuous Ink Supply System (CISS). Daily temperature fluctuations create air bubbles inside ink cartridge. Once air bubble is pushed into supply tube, it alters the ink pressure and creates a cascade of events and stops CISS from working. 

To clear the air, extensive re-prime is required.
Extra Long elbow goes deeper into the cartridge, so the air is not easy to get into the supply tube. Excessive air can be dissolved back into the ink or released by printing/head clean process. Thus reduce "bubble of death" for CISS systems