This brake bias valve was found primarily on Canadian market cars in the mid-1970s and on to the end of importation in 1980. It was also found on the Austin America.
Unlike the earlier proportioning valve which used an internal piston and different tension springs to control fluid distribution, the inertia valve uses an internal ball bearing which holds open the valve for fluid flow to the rear until heavy braking, when it sends all pressure to the front brakes. Note it must be mounted on a bracket at a prescribed angle and orientation. The bracket is shown in drawing for informational purposes and is not included with the valve and is not (currently) available.
New old stock.