[Rugged Steel Brackets, Upgraded Rounded Corners]- Fine Black Powder Coated Barn Door Bottom Roller Rails Tough, Durable, Rust Resistant, Flush To The Floor/Ground, No Screws Protruding On The Bottom, The Door Does Not Need To Be Recessed Slots, doors are not drilled ground. Perfectly shaped with rounded corners, countersunk holes and recessed screw heads, this wall rail protects children and toes from injury. [Easy to install, suitable for many applications]- Heavy duty support roller door rails can be screwed/mounted to the wall, the low profile sliding door rollers look great indoors/outdoors and are suitable for areas like living rooms or DIY projects like rugs on concrete slabs are great for keeping doors/gates in line with walls; comes with step-by-step instructions and is super easy to assemble. Our bottom adjustable rollers contain built-in ball bearings, which provide smooth and easy rolling, unlike other ones with big wheels, only two small bearings, keep the door balanced and stable from both sides, requiring only a small installation space , providing more wiggle room for perfect alignment of the rollers with the door.