Mid States Laboratories Inc.

Thin Tube

About the Thin Tube Molds

The numbers TT1 through TT4 relate to the degree of loss,
and the necessary gain. As the number gets larger, the fitting
becomes more closed and the amount of possible gain increases.

Reasons for Thin Tube Fittings

To better achieve the patient’s goal, it’s helpful to identify the reason for a Thin Tube fitting.

  • Retention: The dome or fitting piece provided by the manufacturer won’t stay in the ear canal because of:
    • imperfect size of dome
    • lack of retention in the canal
    • length restrictions of the tubing
  • Feedback: feedback is still a concern with the dome attachment.
  • Occlusion: occlusion is still a concern, and even with the custom product, there may still be some need for modification. (This was previously not possible with the dome!)

We’re more than happy to help answer all your questions about Thin Tube earmolds before, during, and after the fittings. Please give us a call!

Thin Tube Styles


TT1: Canal without Retention Hook


  • Standard canal mold
  • Completely in the canal (CIC)
  • Fits full size of canal without wing or retention hook
  • Manufactured with an extra large vent, and may be used with SAV
  • Our smallest, least visible and most open TT mold


TT2: #HF Canal with Modified Wing


  • Slightly more visible than the TT1 mold
  • Open canal
  • Beneficial in reducing occlusion
  • 3HF ring is reduced to a small wing at the bottom of the concha for retention


TT3: Canal with Modified Wing and “Thin SAV


  • Standard canal style
  • Area between tube and wing is thicker for a large vent or SAV (10-20% of canal length)
  • More closed canal than the TT2


TT3 1/2: 3HF Canal with Modified Wing and “Medium Thickness SAV


  • Standard canal style
  • SAV thickness is approximately 50% of canal length


TT4: 3HF Canal with Modified Wing and “Thick SAV


  • Standard canal style
  • SAV resembles a stepped back canal (90% of canal length)
  • SAV area extends further into canal and allows for increased gain
  • Most closed of all the TT fittings

Of course, we can make molds using any standard materials, and we’ll friction fit the tubes, too. But we prefer to use Apollo and Marveltex for the best custom friction fitting!


| 600 N. St. Francis | P.O. Box 1140 | Wichita, KS 67201 | P 316.262.7013 | Toll Free 800.247.3669