Approximately 50 – 60 seconds for it to fully expand.
Attenu8 has increased the rebound time so it helps all types of users attain a better fit which is crucial for noise reduction.
If you dislike the rebound time, gently press on the foam tip and insert them directly into your ear canal.
*Do note that it takes a longer time to expand in cooler temperatures and quicker time to expand in warmer temperatures.