FUDGE! I had those very same custom tips on my Phonak Lumity Life aids. My ears started to burn and itch after about 2 days of wearing them. I’ve still got them, but I doubt I’ll ever be able to use them. Mine were actually fit right on the entire matchstick speaker. It was a snug fit, and might have even rendered my aids WATERPROOF as claimed? But I had to replace them with the softer, smoke topaz colored double domes, as that seems the only material I don’t have a reaction to.
I’m allergic to the pink-tinted hard acrylic, the clear acrylic, and the firm silicone as pictured on your aids. My ear canals seem to be made of skin from another planet cuz I can put eyeshadow on without breaking out, wear cheap jewelry without an issue, but only the soft silicone double domes in my dang ears.
For the record, I haven’t tried titanium …