Review on 🌞 Sunco Lighting 12 Pack 4 Inch LED Recessed Lighting Ceiling Lights Slim, Daylight 5000K, Dimmable 10W=60W, 650 Lumens, Smooth Trim Damp Rated, Canless Wafer Thin with Junction Box - ETL & Energy Star by Warrick Dembo

They have exceeded my expectations. Very bright. Facilitated installation. Really good looking. The junction box is metal, leaving enough room for 1 or 2 incoming wires (but not 3). There is a ground wire in the box. The only thing not included are some knockout clips. It's not included and you don't want to run a wire through a metal hole without a clamp. Luckily, they're cheap and available at any hardware store. The great thing about them is that they are very thin. Thinner than drywall which means you can install them with bolts. As long as you have an inch clearance on either side of the stud, the spring clips can go in and hold the light. Much better than decentering the headlights to fit a conventional can around the studs.