If your NHS models are the NX model you could use Rexton, and most likely the other Signia rebranded models, they seem to use the same products/accessories.
Rexton Smart TV Transmitter
Rexton Smart Connect TV Transmitter for Smart Connect Paired Hearing aids |...19
Rexton Smart TV Transmitter. Compatible with: All Rexton Hearing aids paired to Smart Connect device. This version of TV transmitter is the 1st generation model. It connects to the tv or cable box which in turn streams the audio to the Smart Connect,...
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