Long enough for even the longest parts of the French horn (although it's a bit too stiff for some of the smaller radius turns). The shower head attachment is great, I get a large enough pressure with a small amount of water already (holes in the end are really tiny) but I haven't ever seen a leak from anywhere even with the taps opened fully.
Fair warning, if you use this the first time, hold the end strongly in a bathtub or something, or else get yourself, the room and the neighborhood very wet when the hose inevitably escapes from the pressure. Also, open the tap very carefully, since the holes are a lot smaller than your regular shower head.