A roll of bulk vacuum hose from domestic autoparts store works fine for less money.
Four way and three way vacuum connectors:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1A611LS71&year=1987&make=MB&model=300-SDL-001&category=D&part=Vacuum+Hose+Connector

If you need a vacuum hose union, go to a domestic autoparts store with a chunk of hose, they will give you what you need.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/