Spindle Encoder For Lathe

Hello Everyone,
I need to find a Spindle Encoder for my Lathe. I need an would prefer
a complete unit that can be just bolted on. I need a 1 pulse per
Rev.and does anyone have any direction as to where I might find
something that I can use. (I can't build for the reason of a
disability), and would be just a waste of time and material. Want to
run with TCNC Hook Up. Any Help is more than Welcomed. Thanks.