Tube Lock Systems
Standard BTE hearing aids use a 12 – 13mm tube connected to a custom ear- mold that fills the ear canal and holds the tube in place. Replacement tubes not only look and feel better but they help a BTE hearing aid to fit better. Tubes should be replaced every 3 months to get the best from a BTE instrument. Cracked or yellowing tubing will cause feedback and consequent reduction in amplification.
If your patient is an adult you will almost certainly require size 13 tubing, these are available in extra thick, thick, and medium. These three sizes prevent crimping, stretching and most importantly sound feedback from the aids. Thicker tubing contains sound better and reduces feedback commonly caused by powerful hearing aids.
You also need to be aware of what the ear-molds are fabricated from. If it is soft silicone, or soft vinyl material you may need to use a ring or lock with the tubing, often called tube-lock or tube retention. This lock keeps the tubing in place. Without it the hearing aid could detach itself from the ear-mould.
Tube-lock uses a brass ring fitted to a thick or super pre-formed tube. You require a fitting tool to move the old ring off and put the new ring into position. The Tube Retention System uses a plastic permanently fitted ring that does not require a special tool.