I bought 5 in total, one for each 3m of 4 inch blast hose. I use them to adjust the length of vacuum hose to the table saw, jointer, and router table (one length remains attached to the unit) with a 4" Woodstock W1019 fitting on the ends of the "unassigned hoses" to connect the sections to connect to each other. The quick friction fit is sufficient for current work and is easy to adjust to my setup.