An L-type dual-layer composite PE liner bag for 19L stainless steel storage drums, designed for medium-batch photoresist media dispensing. Raw materials undergo ultra-high-purity refining, strictly limiting fine particle and metal ion leaching and eliminating electronic chemical contamination risk at the source. Supplied as a complete set with sealing gasket, dust cover and clips, the sealed structure keeps out oxygen and dust and slows material degradation. The centred opening precisely matches dedicated supply tubes for very low discharge residue, and single-use replacement completely eliminates cross-contamination within the drum — suited to recycling turnover on semiconductor clean production lines.