This listing is for a VINTAGE SONY WALKMAN CASSETTE PLAYER WM-2. The center gear wheel is not cracked, it is either the original or was replaced, I am not sure exactly but it is not cracked. Sold as defective because it has some slight fluctuations in sound when playing, they might disappear with use or might need some further checking and fixing. Also the small battery cover inside the walkman is missing but it will work without it, that cover can be bought for around $20 or something. This walkman has a standard jack so many different brands of headphones can be plugged into it. This walkman uses two standard AA size batteries for power.