Bike trailer hitch
Connect a trailer to your bike.
It needs a flexible coupling so that you can go around corners. This setup uses 32mm i/d radiator hose.
The thing here is a suitable connector to put on your bike to connect this flexible hose to.
The hose just slides on/off, a pin through the hose and "thing" prevents the hose sliding off in use. I use a padlock which also prevents some scallywag running off with your trailer when the bike is parked up.