This product is handmade! It's a bird tent knitted with yarn! I think it can also be used as a bed for other small animals♡ How about it for protection against the cold in winter, as it's warmer than cloth? It can also be used as a bed for other small animals♡ It comes with a carabiner, so you can fix it to the cage. The carabiner material is aluminum and steel. The bottom board is not made of thick material. Please check the size in the photos♡ ⚠︎︎The long-tailed tit is not included. Please purchase with an understanding of handmade items (*^^*) Java sparrow Bengalese finch Society finch Parrot Degu Sugar glider Budgerigar Lovebird