Rare Vintage Girard Perregaux Chronograph,missing caseback, sold as parts

Rare Girard Perregaux chronograph vintage, 34mm x 41mm to lug tips, 18mm lug width, stainless steel snap back case with rectangular pusher...

Rare Girard Perregaux chronograph vintage, 34mm x 41mm to lug tips, 18mm lug width, stainless steel snap back case with rectangular pushers, missing caseback, no strap, silvered dial with black painted numerals, three inset subregisters for minute recording, hour recording and subsidiary seconds, 17J, caliber 285
PRICE ESTIMATE $700 US