The #1 issue issue with FleaBay; it's a crap shoot re: venders. I risked $5 on the first one, and also got a mix of relay boards from several places. The one is 24V but it's screw term not IDC headers.
Can't tell the spacing of the 10 pin headers until they arrive, then seek an IDC cable. Have to find a 4-pin I2C female connector as well.
Just looked for DIN clips; prices from "gulp" to insane. Phoenix is mostly the latter.