If you need the double dome, you aren’t necessarily going to get enough seal from a single bullet dome.
However, these things aren’t always as straightforward as you might think. Some people who should require a more occluded fit, dislike it, while others who should prefer open domes like to have a bit more seal.
At 60dB plus, you should be ok with a decent seal, but trying a lesser option won’t hurt.
I have a double dome in my right hear only. The left is just a single. I was having feedback in my right ear and the double dome fixed that issue.
Your right ear loss looks like the Grand Tetons 
Just a quick update here! I ordered the Phonak double-domes at Amazon, size M. I’ll be jiggered: they are the IDENTICAL size as the S my audi-guy gave me. Augh. The packaging on these two sizes of dome says S and M, but hold them next to each other and they are not even a fraction different in size.
My size L domes are indeed an order of magnitude bigger, but I had to guffaw at the joke’s on me. Apparently, Phonak thinks that just cuz I’m DEAF, I’m also BLIND and can’t tell that their size S and M domes are the same. And here, I administer a slap to my forehead.
I’m still wearing the smaller dome on my left receiver, and while it does tend to slip out of the ear a bit, I just push it in again. Truth is, my left ear can only fit the S/M before noon; then it’d be fine with the L dome. But if I had to change domes on one receiver twice a day, I wouldn’t have time for better things to do.
or colonman_facepalmingcolon or woman of course…add wo in front of man.
It’s in the list of emoticons. Although if you’re hard of seeing it’s not exactly obvious.
But dang! Whaddyagotta do!
I’ve got pretty assymetric hearing loss so I put a power (i.e., closed) dome on the bad year and an open one on the good ear. You may need to adjust the fitting software to handle the difference in coupling efficiency.
Similar question for KS7 open click domes. My left ear is fine with 8mm, but the right ear needs a size smaller. There is no 6mm so I had to go to 4mm … kind of loose.
I’m just now trying Oticon 6mm open domes, but they do not ‘click’ on as securely. What is the risk of separation? Anyone with long-term experience with Oticon domes on Rexton/KS receivers?
Not long term, but I tried one. I pushed it on as hard as I could (and noted as you did that it didn’t click) When I took the hearing aid off, the dome remained. I need help from my wife with a pair of tweezers to remove. Wasn’t particularly fun. I do not recommend. And to be clear, I am talking an Oticon dome on a KS7. It wasn’t a 4 mm though. I think it was an 8 mm.
[Quote] Um_bongoRegistered Provider
Nov '17
Or you can take a set of snips and make a radial cut in the domes to create a tulip version of an oversize double dome. [End Quote]
Has anyone tried the ‘radial cut’ (or maybe just a straight cut with open domes) on open domes? This might be preferable to mixing manufacturers domes in order to retain the very secure ‘click’ offered by the OEM domes.
Are you having a problem sourcing OEM domes? I have 10 and 8. Of course you can mix. I also went to a Costco (I have KS7’s) and they gave me some closed domes I’ll get around to drilling a vent into to get one vent hole going.
Edit: Just re-read your post…Costco has 6. Maybe try another location.
Not sure if you were responding me or other KS7 poster. I’m not having any issues. I was just trialing an Oticon and wondered if the domes were interchangeable as I’d heard that many were. Oops. Question answered.
I also had a size S double-dome come off the end of my Phonak Audeo B-Direct aid and get stuck in my left ear! Luckily, I was able to pull it out on my own, but it seems that if the dome is not seated absolutely perfect on that tip of the receiver, it is prone to coming off. There seems to be a lip, edge, or some-such rim on the receiver to hold the dome on secure … in theory, at least! 
I make a straight cut on one side of the domes because 8mm feel too loose & 10mm are too tight.
[Quote] z10user2
Are you having a problem … I also went to a Costco (I have KS7’s) and they gave me some closed domes I’ll get around to drilling a vent into to get one vent hole going.
Edit: Just re-read your post…Costco has 6. Maybe try another location. [End Quote]
The Savantos “Click Dome” brand open and closed domes came with my new KS7’s.
From my somewhat extensive research, these Savantos domes for Rexton & KS have limited size selections.
…,…,.10mm…8…6…4mm
Open…10 … 8… --… 4
Closed…10…8… 6… –
I tried the Oticon 6mm open dome, but the fit on the receiver is marginal (the fit in the canal was perfect). It worked fine for one day, but I’ll not chance it again.
Did I miss a source for Savantos 6mm open “Click Domes”?
You’d think folks with dome size issues would be clamoring for a custom mold. Why don’t you go this route instead of fussing with generically sized tulips?
Then apologies are in order. Evidently I’m wrong. I’ll review what I have on hand later on and see what’s going on. I have a bit of a collection.
Edit: Ok. Here’s my collection:
10 and 8 double closed (power)
10 and 8 and 6 closed
10 and 8 open
tulips
I am not saying this is exhaustive of all that is available…just what I have. I got most of them from my local Costco and then I got a couple 10-packs of 10 and 8 closed from another Costco in another country (US).
I don’t know if this helps but there you go. I do not have 6 open.
My thanks to recent responders.
A little more search has bolstered my newbie-confidence about click dome sizes. For open and closed, I’m now fairly sure availability is 10, 8, 6mm for closed and 10, 8, 4mm for open for Sivantos products.
This discussion & search soon became TMI (too much information). If interested, see below.
Nov 2016 Signia Product Brochure
Spring 2017 Government Services pocket guide (by Signia)
Just found a user comment in another thread about cutting the open domes to allow better fit.
[Quote]The soft cone that goes into the ear has circular design that if you cut the spacing support around the base of the cone, this action reduces the pressure from the outer rim of the cone on the inner ear and makes wearing them much more comfortable. The cone still fits snug in the ear and sound performance isn’t affected. You can cut the spacing between each rib one at a time testing after each cut. Your not removing any material with each cut. Your just allowing the outer circle of the cone to compress easier in you ear canal making it more comfortable in your ear. [End Quote]
And, a technical Signia article on fitting Click sleeves (vented and unvented) with open dome and double dome comparisons in RIC applications.
Speaking for myself here … my ear canals are strangely prone to swelling and contracting during the day. Drives me NUTS! It started a couple years ago, but in very humid climates, or first thing in the morning, I simply can not get a “custom” mold to fit in my ear. The result is irritating “leakage-squeakage” for HOURS till my ears either expand or contract to fit the custom mold.
That was a prime reason for my switching to BTE aids last fall. I find that the softer, silicone domes fit beautifully no matter what time of day, altho in very humid places, the size (S) on my LEFT receiver can sometimes slip a bit to compromise the seal. I wear a size (M) on the RIGHT receiver, and that seems to fit A-OK 100% of the time.
I’ve seen some flexi-molds online, but don’t know if they are made for leading HA brands like Oticon, Phonak, etc.
Ah, gotcha. I never had any of those issues. My mold is simply tight in the morning, I pull my ear-lobe and yawn to get it in. As the day progresses, it settles in. I found the generic domes just would not seal well enough for me although I did like the way they felt. Perhaps future material technology will bridge the gap between a good sealing custom mold and generic soft domes.
^^^ Yes, if there are two areas that need addressing in my dream-world for HA wearers, it’s: 1.) flexible molds to fit ALL day with true comfort, and 2.) waterproof aids for active folks like me. I have resigned myself to just taking the plunge into snorkeling, kayaking and all manner of water sports DEAF as a paddleboard. I always have folks trying to strike up a conversation with me, and they actually look irked when I say, “SORRY! No aids in. Can’t hear even a fire alarm going off!”
Like I’m making it up or something …