HRS Series HRS-90 9-STRING NICKEL-PLATED ROUND WOUND – 09-90 HRS-81 8-STRING NICKEL-PLATED ROUND WOUND – 09-74 HRS-75 NICKEL-PLATED ROUND WOUND -7-STRING, 11-70 HRS-74 NICKEL-PLATED ROUND WOUND – 7-STRING, 10-70 HRS-73 NICKEL-PLATED ROUND WOUND – 7-STRING, 10-64 HRS-72 NICKEL-PLATED ROUND WOUND – 7-STRING, 10-64 HRS-71 NICKEL-PLATED ROUND WOUND – 7-STRING, 09-64 HRS-D4 DROP TUNE, NICKEL-PLATED ROUND WOUND – 13-70 HRS-D3 DROP TUNE, NICKEL-PLATED ROUND WOUND – 11-70 HRS-D2 DROP TUNE, NICKEL-PLATED ROUND WOUND – 10-70