I hope nobody here uses these leads, but if you do....
I found a good article shared in another greyhound group. If you do have a retractable lead please reconsider and use a decent fixed lead instead. Retractable leads are even more dangerous for greyhounds than other breeds - a greyhound can pretty much get to maximum speed by the time the lead has spooled out with obvious consequences for both the dog and the handler.
I use a retractable lead on willow and a harness have done for years but I never let it out till we get to our quiet spot where there is no dogs at all as she is terrified of dogs we go to a quiet spot or a wouldn't use that kind of lead xx