Review on VANJING Waterproof Automotive Relay Switch Harness Set - 5 Pack, 12V SPDT, 40/30 Amp with Interlocking Relay Socket Relay, 12 AWG Hot Wires by Ashwin Chauhan

This has no freewheeling diode or resistor and is relatively easy to open. If you want to add a flyback diode or similar you should be able to do that - there's just a bit of potting holding the inside of the relay to the outer case so a few small bits with a utility knife and I was able to remove it (requires a little dexterity to avoid damage). In my case I didn't want flyback diodes or resistors so they were perfect for me. It's also easy to remove the terminals (they come out opposite many of the connectors - push on the wire, don't pull). The coil resistance is 80 ohms.