250ml–500ml Water-Level Marked Liquid Sampling Bags for Water Sample Testing

Designed for sample collection and testing, this pouch normally comes as a flat self-sealing bag; a spout or screw valve version can be produced when the sampling method requires it. Three-side or four-side heat sealing creates even, smooth seam lines, helping the filled pouch withstand pressure without leakage and drain efficiently when poured or accessed with a probe. A transparent reading window and printed water-level scale on the front allow quick volume checks, cutting down on manual estimation errors.

The pouch body is typically built from laminates such as PE, PET, PA, and AL, with the structure selected for acid/alkali resistance, light protection, or high barrier depending on the contents. Graphics and level markings are applied together by 1-8 colour gravure printing, giving accurate registration and stable colour. Capacities range from 100 ml to 5 L, with 250 ml and 500 ml among the most common. Bag dimensions, spout diameter, and seal width can be tailored to your drawing, and matching roll film in the same material can be supplied.

Applications include liquid sampling and transfer packaging across environmental monitoring, water services, food and beverage, personal care, and chemical industries. Custom orders generally begin with a customer sample or drawing; after the material structure and print layout are confirmed, a proof is made for approval before bulk production. The factory is located in Dongguan, Guangdong, operates a Class 10000 clean workshop, accepts customization by sample or drawing, and has an MOQ of 10,000 pcs, with production and delivery scheduled to agreed milestones.