Dâ€^TMAddario EXPs deliver the most natural-sounding, longest-lasting coated strings available. Through our advanced EXP Coated Technology, we have perfected the art and science of coated string-making to deliver extended play strings that sound identical to our world famous XLs. Plus, weâ€^TMve dramatically improved the corrosion resistance, longevity and durability of plain steel strings through an exclusive compound tin-plating process. Finally...coated electric strings that deliver longer life, completely natural tone and the feel of uncoated strings. You wonâ€^TMt believe they are coated!