The item shown is a roll of DPM (Damp Proof Membrane) Nylon or construction polythene sheeting.
Purpose: Primarily used in building construction for casting land ("German floor"), lining foundations, and preventing water leaks.
Specifications: Available in various thicknesses (gauges), such as 1000 gauge, and typically sold by weight (e.g., per kilogram or in 100kg rolls).
Features: Durable, water-resistant black plastic sheeting designed to strengthen building foundations.