Be careful:

The silicone tube and cap come from the mould ,every one have gate location,it is very hard to make it is 100% smooth,becuase it is Zero feeling silicone tube .but never effect the functions,never

If your care ,do not buy. 

and the cap have hole ,let the air flow ,not the quality problem

The silcione tube and cap it is easy to broken ,we never maintain your 

And the band is black or grey,it is send at random