






For the new straps, just measure in millimeters the strap width at the lugs and at the buckle. My guess from looking at your picture is your strap isn't tapering so my guess would be the strap on your Mille Miglia GT XL is either a 20mm x 20mm or 22mm x 22mm. Hopefully the strap is the same size as the Jacky watch so you can use that strap!
Cheers,
Anthony