they seem to be 8 Ohm units which would normally be OK for many decoders - but it depends on the particular decoder's requirements. For example, Loksound have provided decoders requiring 4 Ohm, 8 Ohm and 100 Ohm speakers over time.
Ideally the impedance of the speaker should match the decoder's stated requirement and whilst it's not always the case, there is always a risk of damaging the decoder by using something different.
Thanks for the reply Doug,when I return to the room ,I will remove the speaker from the GPS and measure the resistance.Hopefully it will be in range,I will test it's performance and report on here.....................................Peter.
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