Made specifically to go from Dewalt Vacuum DXV06P to Makita Router RT0701C. The router is equipped with a dust guard that the hose attaches to. It is a Makita 195559-1 piece purchased from amazon. Although it was made specifically for these tools it should work for any press-fit application that goes from 1.5in to 1.75in.
The author hasn't provided the model origin yet.