Kanthal A1 is a ferritic iron-chromium-aluminium alloy (FeCrAl alloy) rated for use at temperatures up to 1400°C (2550°F).  The alloy has high resistivity and great oxidation resistance.

It is typically used in furnace applications, such as electrical heating elements in high-temperature furnaces for heat treatment, glass, steel, ceramics, and  electronics industries.

At present Kanthal A1 is the best coil material for e-cigarettes.

The factors that affect resistance are:

Diameter: The thinner the wire (higher gauge number), the higher the resistance per foot. The thicker the wire (lower gauge number), the lower the resistance.
Length: The longer the wire, the higher the overall resistance. The shorter the wire, the lower the overall resistance.
Temperature: The more heat the wire generates, the more resistance it will create.
Current: Determine the current (amperage) you need to heat your kanthal wire.

Characteristics

Material: Kanthal A1           
Length 20m;
Size: 26Gauge=Ø0.4mm, 28Gauge=Ø0.32mm
Shipping weight: 31g
Package: Simple packaging