Thermolyne^® fibrox-insulated heating tape 

Serpentine configured heating elements embedded in tough, pliable, braided tape that conforms to almost any shape vessel for even, direct-contact heating without hot spots. All tapes have high temperature lead wires emerging from opposite ends and separable line plugs. A temperature controller is required.
Standard tape has finely stranded resistance wires doubly insulated with braided fibrox yarns and knitted into flat tape. Heavy-duty version has an extra braided fibrox covering over the standard tape, suitable for direct contact on conductive surfaces.

Thermolyne is a registered trademark of Barnstead/Thermolyne Corp.