If one were to add the diameter of the core to the diameter of the wrap wire times two (the wrap is on both sides of the core), one would get the total diameter of the string. Unless one was DR Strings! DR uses a technique called Compression Winding. This means that the string is wound so tightly that the diameter of the finished string is less that the sum of the parts! More metal for less! DR BKE-10 EXTRA LIFE Coated NPS Electric Strings (10-46) $10.69 DR PHR9 PURE BLUES Pure Nickel Electric Strings (9-42) $6.42 DR PHR9/46 PURE BLUES Pure Nickel Electric Strings (9-46) $6.42 DR PHR10 PURE BLUES Pure Nickel Electric Strings (10-46) $6.42 DR PHR11 PURE BLUES Pure Nickel Electric Strings (11-50) $6.42 DR LT9 Tite-Fit NPS Electric Strings (9-42) $6.04 DR MT10 Tite-Fit NPS Electric Strings (10-46) $6.04 DR JH10 Tite-Fit NPS Jeff Healey Electric Strings (10-56) $6.04 DR ZEH9 ZEBRA Acoustic/Electric Strings (09--46) $7.39 DR ZAE10 ZEBRA Acoustic/Electric Strings (10-48) $7.39 DR ZAE11 ZEBRA Acoustic/Electric Strings (11-50) $7.39 DR ZAE12 ZEBRA Acoustic/Electric Strings (12-54) $7.39