Some may have seen my recent thread with heatbreak issues. I hacked together a solution that worked a little while using a china made 'ed3v6 1.75mm heatbreak'. This was a temporary solution until I could convince one of the Aussie suppliers to sell me a single heatbreak (they get pissy if you're not buying a whole hot end or printer). With that said I've put a good comparison together so others can see why you shouldn't buy the cheaper china option. In the following photos china is on the left and original is on the right. Massive differences are external thread length, internal ptfe capture length & machining quality. I suspect the metals are different but its hard to tell.
You may have been able to get away with the difference in thread lengths but the end on view about five photos above shows not only a different depth of bored hole but a piece of swarf stuck to the inside of the hole. Not sure which end of the heatbreak this is but if it is the end for the ptfe tube then the length suggested by e3d would be completely wrong too. Pity e3d don't sell the individual parts. I rob another assembly for the heatbreak so I can cleaning up the previous one later. As noted e3d didn't/don't? sell individual parts (or maybe just your supplier?) but even with e3d take care what you order as they don't know which setup you have so an incompatible hotend assembly is quite likely on the cards.
They do, you can get every part of the V6 separately. Heatbreak for instance: http://e3d-online.com/v6-Heat-Break-1.75mm