stencil-strength

Refers to da durability/longevity of da oilboard material used to make spray-paint symbols.

I never purchase "bargain-basement" lettering--kits, since I find that they are usually sorely lacking in stencil-strength... sure, the "pro-grade" kits do indeed cost more, but they tend to last a lot longer and consistently produce sharp-edged paint-markings for many years.