[Mondial]

The flex resistors are actually wirewound resistors made from resistance wire wrapped around a flexible asbestos or glass fiber core.They were typically used for stable low resistance values which were difficult to get in carbon.

The wattage rating will depend on physical size. A one or two inch long resistor might be rated at a watt or so. Unless the flex resistor is extremely long or large, the 5 watt would seem to be a safe replacement.

Is the existing resistor open? They are usually fairly reliable and typically hold tolerance well.