My 1972 350SL with same Djet system uses the icecube style relays. Functionally, they should be the same. But the pin arrangement is likely different.

To use them, you may need both a relay and a base. I have pinout somewhere, but pic below gives the idea. Finding a few good used round ones would no doubt be best bet.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5