Marko's trash liners are made of low-density polypropylene to give you the most bag for the buck. Linear Low Density Polyethylene - this resin is highly puncture and tear resistant. These properties make this the best choice for applications where additional strength and stretch are required. Works well for waste with sharp or jagged edges. High-density plastic liners are brittle and tend to split abruptly when full. Low-density liners stretch without splitting, although holes may appear when over-filled.