This is part of the STS top of the line (Deep-Design Series) i.e. most advanced and cost -effective portable bullet trap on the market in the most compact form, with 12" x 12" target area. Designed for .22, 9mm, .45ACP, 0.40 S&W, 9mm, .357 and .44 Magnum calibers and also 5.56 / .223, 7.62mm, 6.5 CR / Lapua ammo, as well as other energy-equivalent rounds. Easy to assemble, made from steel for exceptional durability, includes a high quality ballistic rubber panel positioned in front of the steel cage that will prevent bullet fragments and lead dust from escaping the cage. Using an innovative design, unlike other traps in the market, this trap is completely enclosed, so the potential lead fragments will be trapped inside instead of polluting the environment. It is highly recommended to fill it with rubber mulch which will significantly reduce the lead dust generated due to bullet impact. The filler material also makes it quieter and increases trap's lifespan. The basic rubber mulch is inexpensive and can be found at most hardware stores or you can purchase the ballistic type (higher quality, longer lifespan, more effective) from our website. The trap has a handle and a top door for checking level and adding the rubber mulch material, as needed, over time. Rubber panel replacement available under ASIN: B07SSVW39W. If you need a much stronger panel 2" thick, then order ASIN: B07SSVW39W. The lifespan of the ballistic rubber panel is highly dependent on the caliber and type of bullet used. For example, the FMJ type rounds will not be as destructive to the panel's lifespan as the FTX, HP, XTP or SP bullets. Warning: Must be used within the general safety guidelines for bullet traps (maintain a safe distance, must avoid shooting the trap sides or edges, always aim for center of the trap, ensure that trap is placed on a stable surface, careful inspection of backplate and sides for damage or gaps, replace front panel when holes/gaps start developing, check overall condition.