Seiko Hi-Beat automatic stainless steel lady's bracelet watch, ref. 2706-7010, oval blue dial with baton markers, day/date apertures and centre seconds, mesh bracelet with adjustable clasp, 22mm (at fault)
Arttu Junnila on Twitter: "Here's a comparison of the balance with a more normal sized one. Now, a hi-beat balance needs to be smaller than a low-beat one so it can oscillate