Cinturino in pelle italiana smerigliata pelle bovina per Casio PROTREK serie PRG-600/PRG-650/PRW-6600 cinturino per sport all'aperto 24mm _ - AliExpress Mobile
found this PRG-50 in a thrift shop for 4€. and it works, just need to change battery and download the PDF of the manual : r/casio