[lamski]

I have a pair of musician westone custom molded earplugs with the ER-9 button filters.  The filters are removable and I was thinking I could turn these molds into a nice IEM.  I tried plugging my CX300s into the molds but they didnt fit properly and didnt sound right.  Is there a nice sounding off the shelf IEM that can seal properly to the button plug hole?  It would be nice to use these as custom plugs as well as custom IEMs.

 

[IZCool]

ACS have a pair of earphones that are designed to fit in place of the ER-9/15/25 filters.
http://www.hearingprotection.co.uk/index.php?option=com_content&task=view&id=59&Itemid=115
 
Just be careful that you don't wear out the earmoulds because as you change filters more often the filter will be less strongly held by the moulds.