This is a power inlet plug that prevents cold air from leaking in when you have your power plug attached. On Knaus caravans there is a service hatch rather than an external power inlet on one of the caravan walls, where you feed the cable into the service area from underside the caravan. The inlet on the Knaus caravans will cause a lot of air (cold) to enter the cabin. This plug will fix that and fit very snug into the hole for the cable and still make it easy to install and remove.

You also need 2 self-adhesive sealant strips about 300mm long each. Width 10mm by 3mm thick with a "W" profile as per the pictures. The strips are common ones used for sealing doors or windows etc so they should be easy to find. Once the strips are installed apply white grease or any suitable lubricant onto the strips to allow for an easy airtight install.

Works wonderful and gets the job done of preventing air leaking into the cabin!