This is exactly what you would expect from the studio-type listings in Kailua--the bare essentials and perfect for a place to sleep in between the beach and exploring the island. My wife and I have stayed at three separate places so far in Kailua, and this location by far was the best location, centrally located and biking/walking distance from food and the beach. The room had plenty of extra towels for guests as well as body boards, bikes, umbrella, and snorkel gear.
Not necessarily a drawback, but something to note: the property that this listing is on has another studio rental, the property owner, a long-term tenant, and any guest's the owner may be hosting (her son was there at the time of our stay). While the listing is indeed private, everyone on the property is free to roam the backyard, and the owner spends much of the day in the backyard or in the lanai connected to the house. She never bothered us or invaded our privacy, but if you are hoping for a truly private and disconnected experience, please consider this.