Adapter, fibre washer, calibrated fuel level indicator tube
Made to fit Amal MK1 concentric carburettor,
Screw on to float bowl, Align black line on fuel indicator tube to top edge of float bowl Gasket.
Turn on fuel tap, check fuel level on indicator tube, 40 thou, 1mm either side of red line is recommended fuel level, for your primary circuit
The very best of luck 🤞