Thermal transmitter fitted in the cylinder head from 1970 on until its demise on the 1990 Coopers this part was the same as GTR143. One number was original fitment and the other supplied as the spare part by Unipart.
Fits 998 1275 and cooper S Mk3. The correct original temp gauge for this usually had the rounded bezel wheras the pointed type bezel usually used GTR104 on MK1/2 when voltage stabiliser is fitted.