6Choosing the correct coupling for standard xReceiversDetermine the correct dome size based on your otoscopic examination of the ear canal.Select the dome type based on the audiometric requirements and fitting ranges shown on this page.Allow the dome to fit comfortably in the ear canal.Open domeChoose for:• Instant fit• Open fitConsiderations:• Occlusion freeClosed domeChoose for:• Instant fit• Semi-occluded fitConsiderations:• Extended fittingrange over opendome• Some occlusionPower domeChoose for:• Instant fit• Occluded fitConsiderations:• Extended low-frequency response• OcclusionSleeve moldcShellChoose for:• Custom fit• IntelliVent technologyConsiderations:• Comfort• Possible occlusion• Impression required dometoo smallgood fit250 500 1000 2000 4000 8000-100102030405060708090100110120HzOpen domeClosed domePower dome/sleeve mold