The anti-submarine strap attaches to the rear of the chest strap and at the front has a loop for the seatbelt to go through.
Measure from the top of the chest strap between the shoulder blades down and under, and through to the lap belt.
That measurement is all we need to provide the best fit anti-submarine strap
Adjustment of the anti-submarine strap can be made by varying the positioning of the Velcro strip at the back.
Direct Replacement for