A2 Birdcage flash hider* Overall Length- 1.750"* Weight- 1.92oz* Heat Treated for strength and durability* Phosphate Coated for corrosion resistance* Milled flats for easy installation* Fully Precision Machined in House at KAK IndustryCrush washer not includedCrush washer guide-1/2-28 556- Select 1/2 crush washer5/8-24 308 - Select 5/8 crush washer5/8-24 458 Cal - Select 5/8 crush washer5/8-32 458 Cal - Select 5/8 crush washer1/2-36 9MM - Select 1/2 crush washer1/2-28 9MM- Select 1/2 crush washer9/16x24 40 Cal - Select 9/16 crush washer578-28 45ACP- 9/16 crush washer1/2-20 22LR - Select 1/2 crush washer