I have a nearly new extra long twin size electric blanket. It can be used for a twin bed (obviously) or one side of a double, queen, or king size bed. Works well and no tears, stains, or marks of any kind. We bought a king size with dual controls and don't need this any more. Probably only used for a few months. It comes in a plastic sack for storage. It's a silver/grey color.
Even the least expensive ones on Amazon go for about $40 and up. I recall paying about $65 for it.