Well I purchased this as a bit of a test to see what improvements I could get out of an old controller, you know the ones, reserved for multiplayer as they are a bit beat up, rubber coming off the sticks, sticks starting to drift to the left as you're playing.
For the low price and free p&p you get a product that is delivered quickly, packaged well and containing all the kit needed to re-vitalize a controller, you even get the screwdriver needed to open it up! My only gripe is the D-pad really, it is a 2 piece affair and the 2 pieces I got did not fit together correctly, I have tried the top section on the old bottom section of the D-pad but it doesn't feel as sturdy as before. However this is a minor concern since the D-pad from an old controller is generally in good condition compared to the rest of it and you can simply use that instead.
In short my old controller feels good as new now (most importantly now with sticks that don't drift and are more comfortable to use) and off the back of that success I have ordered another shell for my other "multiplayer" controller. Very happy customer.
As an advanced warning to first timers (I had a crash course in this this morning!), there is a screw under the label in the battery pack socket so don't try and force the controller apart without taking it out first, you will need a small phillips head screwdriver aswell to remove the old D-pad if you need to transfer it to the new shell. Also, be careful when removing the circuit board from the inside of the controller shell, the post that pesky screw from the battery socket screws into has a nice grip on it so work it out slowly. If you get stuck there are plenty of videos/guides out there to help!