7mm x 1.0 - Oval Beetle
https://www.ebay.co.uk/itm/Shift-Gear-Knob-Adapter-Reducer-7mm-x-1-0-ID-Threaded-Bush-Metric-16mm-OD-Lever-/160817038576
10mm x 1.5 - Split Screen
12mm x 1.5 - Bay window
12mm x 1.5- 58 and on Beetle
12mm x 1.5 - 85 and before T25
12mm x 1.5 - MK1 & MK2 Golf, Caddy, Polo
https://www.ebay.co.uk/itm/Shift-Gear-Knob-Adapter-Reducer-12mm-x-1-5-ID-Threaded-Bush-Metric-16mm-OD-Lever-/150705177212
Any Questions please ask