AIGI 16W is a specialized braided mechanical packing (gland packing or compression packing) from AIGI Environmental Inc., designed primarily for valve sealing applications. Unlike the standard AIGI 16 (which is braided PTFE yarn impregnated/coated with high-purity graphite for general pump and valve use), the "W" variant uses 100% expanded PTFE (ePTFE) fiber.