MH750 is slightly different from MH755, there was a graph somewhere which says the MH750 has a bigger bass boost compared to the MH755.
MH750 is a normal length iem that comes with a mic and is the free earphone that comes with the Sony Xperia smartphones while the MH755 is a super short IEM which comes with sony's bluetooth player.
There are 2 ways of getting the MH755.
1) Getting one of the sony bluetooth player and you can be 100% sure that it is genuine MH755.
2) Getting one from the resellers. From what I know, sony was making these in huge quantity. Therefore the only way to get them is in huge boxes like these:
More information from one of the sellers from taobao for the white MH755(selling at 20rmb):
1) These required burn in.
2) The white version is new old stock from 2013 ( I finally understood what the seller really meant after reading the sentence for a few more times)
3) One order can come in 10 thousand earphones, that's why the price is cheaper than cabbage. Super good price to performance ratio.
4) Really have to respect Sony's manufacturing and choice of raw material. These have been in the warehouse for 5 years, no yellowing and no stickyness.
5) BUT!! the black version of MH755 is very very rare, which is why i sell them at 80rmb. So whoever is selling lower than this, you should know (implying that it is fake)
6) One way to see if it is genuine/authentic, look at the date and serial number:
Authentic ones should have the same number at 3 places:
1) 13W36 (made in 2013 week 36)
2) the first 4 character of the serial number is 1336
3) there is another 1336 on the wrapping packages.
Disclaimer: I just try to translate what I see to share information for all those who are interested in the MH755. I am in no way related to the seller. Some of the information do seem fishy to me, but this is one of the top sellers for sony accessories in taobao.
I did order from taobao using taobao forwarding agent and the MH755 is on the way to me. I do also managed to find a used sony bluetooth player that comes with the black MH755 in my local marketplace(yet to receive them).