250 Gauge Polythene Layflat Poly Tubing Heat Seal Bags Range of Sizes Available Made from medium duty 250 gauge (62.5 micron) polythene, 335m long rolls (most sizes), suitable for heat sealing. Cannot be used for vacuum packing. These high quality Polythene Lay Flat Tubing rolls are designed to be used to package items via a Heat Sealer. Made from 250 Gauge Virgin Polythene, this tubing is very strong and durable. Please note dimensions refer to the product when flat. Packing the tubing will decrease the available width.