FLAK Tech Features: Solid Brass Adjustable Tire Deflators, Air Down from 0-90PSI Normally there needs to be about 10 psi difference between the starting tire pressure and the desire tire pressure for the deflator to start2. Air down all 4 tires simultaneously to a preset pressure.3. Simply screw onto your tire valve to automatically deflate all tires to yourpreset pressure. Fits standard tire valve size.4. Tested, Proven, Reliable - Brass, and rust free springs and inner components.5. Made with brass and rust free inner springs and components. FLAK Tech Descriptions: 1. The Adjustable Brass Tire Deflators made with brass and rust free innersprings and components.2. Simply screw onto your tire valve to automatically deflate all tires to your preset pressure.3. Once you have preset the valve you will not have to set them again, unless you wish to change the pressure setting. intact with car paint, wiper blades or plastic trim, as this may cause damage. FLAK Tech Instruction: Step 1: Deflate a spare/extra tire to your preferred deflation pressure. Step 2: With the lock ring and adjusting cap wound down, screw your deflator on the valve stem. (Be sure to make sure the threads are clean and in good condition)Step 3: Loosen cap (counter-clockwise) until deflator pops open, then immediately tighten cap to the position where the air stops exhausting. Step 4: Turn lock ring up to adjust cap and tighten. Step 5: Installation is now complete and set to your preferred deflation pressure. FLAK Tech Specifications: Material: BrassPressure Range: 0-90 PSISize: 41 x 17mm Quantity: 4 pcsBest Suited For: 4x4, Off-Road, Sand, Mud, Trucks, Package information: Package weight: 160g/5.6ozPackage size: 60x50x30mm/2.34x1.95x1.17inGeneral Box Package, Package included: 4 x Tire Deflators.