Insulation cover security lock for Unnukka. A safety locking strap for locking hot tub covers, preventing unauthorised persons and small children from using the hot tub. The ends of the strap are fixed permanently to the sides of the hot tub and the strap is cut to the correct size based on the size of the hot tub and cover. The other end of the strap is equipped with a lock operated with the included keys. Locking the strap prevents the cover from being accidentally opened.