Simply put, gel overlay is a technique used to create a resilient, natural-looking finish for nails. “It involves applying a gel product directly onto your natural nails to add strength,” explains Streets. Perfect if your nails are weak or prone to breakage, gel overlays offer extra durability and give support to natural nails while smoothing over any irregularities or texture in the nail, like ridges or bumps. Gel overlays are usually clear or nude. “They also create the perfect base layer for nail art or polish,” says Streets. Crucially, though, gel overlays don’t add length to your nail, so if that’s what you’re after, then nail extensions enlisting acrylic or builder in a bottle (BIAB) would be a better choice.