It came from a HR194qx. I'm told the the gearbox will fit several Honda mowers like the HR216, HRD536 and HRH536.
No cracks to casing and rollers turn freely. The rollers will only fit the 19 models like the HR194 & HR1950.
There is fluid leaking from the shaft in the last picture, assuming the seal needs replacing due to standing for some time.