For the price, this Draper drain unblocked is good value for money. It is fully 7.5 metres long and solid enough for occasional use. I used it on a blocked sink waste pipe 40mm diameter with several 90 degree bends. It requires a bit of juggling and twisting to make it round the corners and more winding and juggling to deal with the blockage. The wing nut takes a moment to clamp and release the wire but holds it well without having to be particularly tight. Some care is needed holding the pistol grip to avoid the wing nut catching on the back of the index finger. The coiled wire is greased from new (I assume to protect from corrosion) and the wire does fill with water when in use. I popped the circular cover off the back, emptied out the water inside and left it next to the boiler to dry overnight. I later put some motor oil on the wire so hopefully it will be in good order for next time. In summary, definitely recommended for DIY, maintenance team or any other occasional user.
I found this tool to be useful, and it worked well on a first use., though it didn’t clear the blockage. From the description I had expected it to be effective through 7.6 m. However, I laid it out on the floor to mark off 1 m lengths, and found that it was only 4 m long. I contacted Draper tools who told me that the 7.6 m is the stretched out length.