Cleartone Drop D tuning electric guitar strings 11-56, gauges 11-15-20-36-48-56. Cleartone Heavy Series are designed for people that play hard. Very Hard. Made by Cleartone, the leader in Premium Guitar strings. With heavy duty reinforced construction and enhanced core-to-wrap ratios, Cleartone Heavy Series are designed to be more powerful in every aspect. All six strings have the patented Cleartone VolumeBOOST treatment, which makes the strings up to 10% louder than uncoated sets and 36% louder than the leading coated set. Your new set of Cleartone Strings also feature our ToneLOCK technology to keep your strings sounding brand-new up to 5 times longer.