The description "21/2×21/2, Density seventy eight×48" refers to the specification of the material and is generally used inside the textile industry to indicate the shape of the fabric.
Here's what every parameter approach:
Specification (21/2×21/2): This shows the yarn depend and construction of the material. In this case, the material seems to be woven in a 2x2 twill weave sample. The numbers "21/2" denote the yarn size or rely. The first variety before the cut back refers back to the warp (vertical) yarn, and the second quantity after the cut down refers to the weft (horizontal) yarn.
So, "21/2" manner that in a square inch of the fabric, there are 21 ends (vertical yarns) and 21 selections (horizontal yarns) in a 2x2 twill pattern. This can mean a reasonably tight weave.
Density (78×forty eight): This parameter shows the thread density or thread rely of the cloth. It specifies the quantity of warp and weft yarns according to inch (or centimeter) of the material.
Seventy eight Warp (Vertical) Threads in line with Inch: There are 78 yarns in the vertical path inside one inch of the cloth.
Forty eight Weft (Horizontal) Threads consistent with Inch: There are forty eight yarns in the horizontal course inside one inch of the fabric.
The material described seems to be a 2x2 twill weave with a reasonably tight creation, given the higher count number of warp threads (seventy eight) as compared to the weft threads (48). This type of material, being military camouflage water-proof material, is probably designed to provide both durability and resistance to water penetration whilst having a camouflage pattern appropriate for army applications.
It's vital to note that the material composition, end, remedy, and further specifications past the weave and thread matter, consisting of the type of fibers used (e.G., cotton, polyester, nylon, etc.), unique finishing techniques, and additional waterproofing techniques, also considerably impact the general traits and performance of the fabric.