They say it is a 19 mm HLB, but that does not match what Davis DeVos wrote back in 2005:

Shaun,
Here is the list to the best of my knowledge:

Early style GF (double grains for linking links):
HL 19mm 2446 Autavia
HLA 19mm Camaro
HLB 20mm 2446c Autavia
HEL 18mm 2447 Carrera

Later style GF (single grains for linking links)
HLC 20mm Carrera
HLD 20mm Autavia
HLF 20mm Autavia
Hope this helps,
Cheers,
David

I contacted the seller and he maintains that it is HLB and 19 mm.

If we all put together our knowledge we can make the definitive list. Come on and post what you know!

For my Autavia 1163 I have a GF 20 mm HLF.

Peter, Denmark
www.watchsite.dk