It (NEMA FR-4) is a glass fabric epoxy composite that is a lower resin content version of NP130. NP130HF is engineered to provide higher flexural strength, higher flexural modulus (stiffness), and resistance to warp and twist than other NEMA Grade FR-4 products. The product is also more dimensionally stable than some similar offerings. Users give the product high marks for its performance in applications such as printed circuit board testing. NP130HF meets or exceeds the requirements of MIL-I-24768/27, Type GEE-F.