Center Hole Open?

I have Phonak Audeo V90 hearing aids, with medium open domes. My question is, should the center hole (over the wax trap) be open or closed? In the domes I have the center holes are closed, but I see pictures of open domes where the center hole is open.

http://www.hearingaidparts.co.uk/index_htm_files/71166.jpg

The centre hole opens both sides and is closed above like in the picture that Rasmus has linked to above. Wax can clog the hole but you can clean them by taking off the domes and using warm soapy water or alcohol wipes. Just make sure they are dry before you put them back on the receiver. If they are getting loose you should replace them. Check the wax trap also while you have them off.

Thank you both. The picture seems to show that the center hole is open, along with the holes in the sides, but the domes I purchased recently have closed center holes. Should I cut those to open them?

No, I think you are misinterpreting the picture. The top of the dome is closed with two tiny holes just below the top on either side. If your new domes are Phonak brand open domes then they will not require any cutting. The very tip is closed to protect the receiver and help to prevent the wax trap from just filling with wax quickly. There is a band of silicone across the top of the domes. There are six larger holes spaced around and further down the domes. If you have a different brand then check with the supplier if they are compatible. I have the same medium open domes and they do not require any modifications. If they are Phonak then they will usually come in a clearly labeled pack.

OK, yes, I see the small hole now. Thank you!