M110 - Super Fine Welded Mono Lace
The most natural hair system we have would be our M110, which is the Super Fine Welded Mono Lace hair system. It comes in an 8"x10" and can be cut down to any size. The reason for why it's the most natural and probably would be undetectable is because it typically has 1-2 strands and is single hair knotted at the base. While most other models are double knotted. The knots as well, are invisible and clear which helps to provide a transparent blend into the head/scalp area. The stock hair density for this model is 90% light density all over.
Also to note with this unit, if you take a look at the base material, on the inside - it does have a shiny sheen to the model.
M115/M116 (Swiss Lace)
If you want another suggestion, the Lace series is also a good choice. Specifically the French and the Swiss Lace. I would recommend the Swiss lace because when you hold up the Swiss hair piece to the light, you can see the translucency of the hair knots (2-3 strands per knot) so it'll blend in nicely and is the most natural between the two. French lace also provides a natural look too but it has more hair density than the Swiss or the Super Fine Welded Mono Lace. Therefore it's a bit more durable and natural but not as natural as the Swiss.
For the Swiss lace we have two models. The M115 which is a full Swiss lace and it comes in the 8"x10" and can be cut down to any size. We also have the M116, which is the Swiss lace with Poly Coating on the sides and back. The M116 is the only one that comes in 3 different sizes. Size small (6"x8"), size medium (7"x9"), and size large (8"x10"). For the Swiss lace series, the hair density is typically 100% at the front, while the rest of the hair unit is 90%.
M105/M106 (French Lace)
The French lace also has two models. The M105, which is a full French lace and that also comes in the 8"x10" and can be cut down to any size. The second model is the M106 (6.5"x8.5"), which is our French lace with Clear Poly Coating on the sides and back. For the French lace series, the hair density is typically 110% at the front, while the rest of the hair unit is 100%
The life span of the Super Fine Welded Mono Lace, French and Swiss series are typically 2-4 months, depending on how well you maintain the hair piece as well.