Perhaps others have covered this and I don't already know. Perhaps there are cheaper or better options out there, but I don't know.
Here is what I do know, $6 at autozone and I have a part number that works.
The 17.5" blades from my 280slc are the same length as 18" blades in the store. Since refills are no longer sold, you just buy the whole arm (and deplete the earth's natural resources for no reason). So here is what I bought:
It might not be so easy to tell from the pictures, but the gold-ish clip at the end of the plastic reinforced (not metal reinforced like the inserts I removed) insert is what holds the blade from sliding out one end or the other. It is very easy to squeeze and slide the blade insert out of the new one without any damage. Then it just clips right into place in the original stainless blade holder. There is nothing at the other end holding it in.
Black blade is what came with the $6 value craft blade. It looks nearly identical to the boast blade. Heck, if you don't want to pay an arm and a leg for blades that would look OEM, strip these down to bare metal, or just paint them silver.
This may not be original quality, but it beats the blade that was falling apart.
Also, I think that maybe SLC cars got 17.5 (aka 18") blades and SL cars got 18.5" (aka 19") blades. This was for my 280slc. So I obviously used 18" for that reason.
The value craft blade was $6 at Autozone. I have read that MB wants closer to $16. There are many options at Autozone in the $12-18 range, but at those prices, I would buy MB. This was the cheapest, and not what the guy in the store recommended to me. He recommended something much more like the original with rubber stops instead of the metal clip on the end. I think it was $9, and I think I might have been more likely to ruin it. So I went the cheap route.
Thought I'd share since I don't recall seeing this covered here. Sent from AutoGuide.com App
. R107 Parts Wanted: washer bottle
(1978), blue r107 visors, 107 trunk spare tire well, 107 headlight wiper arms w107 FS/trade/giveaway:
4 silver BBS RS009 8x16 et11 (won't fit front of 560sl without spacers and smaller lips), D-jet parts, 1975: (wiper motor, multiswitch, coil, injectors, etc.), US headlights, a black 1973 450sl