Use both products for ultimate strength, or use the one that best suits your needs. Rubber Base CoatReplaces your regular Base Coat. Best for flaky or uneven nails.Adds a little thickness, as it is thicker than regular Base Coat. Thickens your mani, but still bends & flexes with your nails. Builder GelAn additional layer after your Base Coat.Best for weak or bendy nails.Adds extra thickness, as it is an additional coat that is able to be layered.Has a hard finish, decreasing nail flexibility & bending.BothHelp your gel manicure last longer & promote growth. Create smooth, even surfaces that make the following coats easier to apply.