Usage Tips: Fitment: For all 1978-1987 full size trucks with disc brakes in front and drum brakes in rear. 2WD and 4WD, 1/2 ton, 3/4 ton, 1 ton. Includes P30 chassis frame. Features: This brake valve is a 5-port valve and can be left, right, or bottom mounted. Valve has 9/16 inch-18 ported rear brakes and dual 3/8 inch-24 ported front brakes. Connections from the master cylinder are 1/2 inch-20 and 7/16 inch-24. Material: High-quality aluminum alloy, wear-resistant, sturdy, and durable. Quality: Professionally manufactured, stable performance, long service life. Name: Brake Proportioning Valve Model Number: Disc Drum Brakes Proportioning Valve Size: 17 cm / 6.69 inches Type: Disc Drum Brakes Proportioning Valve Color: As shown in picture Material: Copper Package Contents: 1 x Brake Proportioning Valve Note: Light reflection and different displays may cause the color of the item in the picture to vary slightly from the actual product. Measurement allowance: +/- 1-3 cm.