I had never heard of this machine, so I Googled. Found the following info:
http://www.amazon.com/Rex-rx-607z-Po...m/B003S276JK/2
http://www.westchestersewing.com/rex/rx_607/
http://forum.woodenboat.com/showthre...sewing-machine
It appears to be an industrial-style machine suitable for sail making and working with heavy materials such as leather. It isn't a machine that would be attractive to most quilters, I would think.