Audiologist or Hearing Aid Dispenser instructions:


1. A full impression is required of each ear. It must include the full helix, crus of the helix, tragus and anti-tragus. We require deep ear canal impressions that completely pass the second bend of the ear canal. (Be sure to examine the ear canal for any obstructions or inflammation prior to taking the impression.)


2. We require impressions made of silicone material and recommend a high viscosity impression material.


Examples: Westone Siliclone S-50, XL100 - XL300 tub material, etc. Shore value should be around 30, but can be higher or lower. If you have questions, please contact us.


3. The impression must be an OPEN MOUTH TYPE. Use a 1-2” bite block during the impression process to reduce jaw movement. This will yield a better seal in the final product.


Customer instructions:


After you receive the impressions please mail boxed impressions to:


The Listening Stack

Attn: TLS Sound Labs

216 Mt. Hermon Rd. Ste. E-368

Scotts Valley, CA 95066

(855) 693-2771 Toll Free


Be sure to include your name and receipt from your online order so we can match the impressions to the order.


If you are unsure of the ear impression meeting our guidelines, please take pictures of them from multiple angles and send them to For questions or concerns about these instructions, please contact our support center at