These thin tubes are for Oticon hearing aids supplied by NHS. Oticon Corda 2 and Corda miniFIT thin tubes - Price is £5.95 per tube or £8.95 for a pair. Corda 2 vs Corda miniFIT - both types of tube can be fitted to Oticon NHS hearing aids like Spirit Zest, Synergy and Engage,BUT.
eBay