This is the simplest and cheapest way to make sure you don’t lose your hearing aids on a hiking or canoeing trip (such as this). Works with any BTE (Behind the ear) type hearing aid. Bulldog clip, (dyneema) string, two simple slip knots. Attach clip to back of shirt collar. Cost: cents. Cheers.
3 grams is not a bad (weight) spend to save yourself a few thousand dollars!