Horizontal Expandable from 17" to 25". Includes 4 large wire panels and 4 small panels which you can easily adjust panel position according to under sink space and fit drain pipe position. To prevent the things falling down, all panels has extra high guardrail.Made of metal with powder silver coating. Better anti-rust ability and long life time. It needs to be fixed up through screws with tools. With package, there will have 4 screws and step instructions. Our special frame with this quality ensures 2 Tier Expandable Shelf Organizer can holds above 22LB.There is a wire on the under sink shelf side. This metal wire isn’t a guardrail but a fixed function design. With wire fixed function, Under-Sink Shelf can be reduced shaking and rack frame can sturdier. On udgraded edition sink rack, this wire has been fixed on pipe instead of removeable design.