Tone color is thick.Strong durability.The surface of the alloy is multilayered.Long time is not oxidized.Suitable for senior guitarists.Adopt medium carbon steel hexagon core and full automatic winding technology, smoother and softer.The nickel-alloy material makes the sound more plump and . 4pcs/set VX120 Strings 040-100 Nickel Alloy Vigorous Tone StringsModel: VX120Inner Material: Hexagonal CoreExternal Material: 10 % nickel alloy wireColor: As picture showsSize:G: 040 inch / 1.02 mmD: 060 inch / 1.52 mmA: 080 inch / 2.03 mmE: 100 inch / 2.54 mmMaterial: Hexagonal Metal CoreProduct packaging size: 18*15*1cmPackage Contents:1* Strings (4pcs/set)Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.