That’s Polyken tape / Pipeline corrosion protection tape.
What it is:
Polyken is a brand of cold-applied tape wrap system for steel pipes. The roll in your photo has the Polyken label inside the core. It’s usually a butyl rubber adhesive + PE/foil backing.
Used for:
1. Pipe corrosion protection - Main job. Wrapped around welded joints, fittings, and exposed steel pipelines to stop rust/corrosion. Oil & gas, water lines, fire lines.
2. Cathodic protection complement - Goes over pipe before burial underground/underwater.
3. Joint wrapping - After welding, you coat pipe with primer, then wrap with this tape + outer wrap for full protection.