DR Strings FAT-BEAMS Bass Guitar Strings 4 String Medium 45-105 FB-45Stainless Steel Bass Strings wound on round cores. Fat Beams are compression wound to produce fat mids, bright highs, and that distinct edgy Fat Beam sound. Hand made with the finest American stainless steel available, wound on round cores for increased flexibility and tone. DR Strings are handmade (not machine made) because our expert string makers are capable of making micro adjustments needed through the winding process for the best sound and feel