This a vintage 18k white gold manual wind Patek Philippe 3430 probably from 1967 to 1968. Its size is 26.5mm x 26.5mm with thickness at about 7mm.
19800 beats per hour with Geneva Seal. It's calibre 23-300.
Accuracy is pretty good at +2 second/day.
The white gold hands and baton hour markers are shinny and stain free.
It goes well with long sleeves shirt as it just so easy slipping underneath the cuff.