An expandable hose is quite short and compact when it's empty, but its width and length double when the hose fills with water. The expanding hose material exerts a force on the water when it expands, and this actually increases the water pressure

You can connect two expandable hoses together. There are a couple of technicalities, however. The two hoses need to have the same diameter at their opening and must have opposing male or female ends to be able to connect. If either of these issues is present, you'll have to use an adaptor.