OMEGA, Speedmaster, chronograph 'Straight Writing'

Case size: 42 mm
Material: steel
Movement: manual, caliber 861
Year: 1971
Crystal: plastic crystal
Bracelet: original bracelet, folding clasp, ref. 1171/633
Reference number: ST 145.022
Serial number: 31.622.523
Case number: 145.022-69 ST
Accompanied by: Omega Extract of the Archives

Please keep in mind that an overhaul might be needed, since no service history is available.