Running Ultegra di2 6770 and i want to increase its range to accomodate a 32t ( or even a 34t) cassette, are the Wolftooth roadlink copies on ebay that can be had for a few quid any good? Or is it worth shelling out another 20 quid for a genuine one.

They are not quite as well made but for the price you can afford two or three and still be in pocket while testing for failures, the real thing does seem awfully expensive when it’s sitting so small in the palm of your hand.

SunRace make a very good alternative.

sunrace one works perfectly

I cant seem to find one by sunrace.

Yes they are absolutely fine, I’m using one with an 11-40 cassette.

https://www.sjscycles.co.uk/gear-spares/sunrace-rear-mech-extended-link-for-wide-ratio-cassettes/

I picked up a few of the super cheap £1.75 ones from eBay.
They’re really poor quality, well the alloy bolt is, the actual cage thing is ok but by the time you find and buy a decent bolt it’s better to buy that sunrace version.

I’ve had two from ebay.

Worked just as well as could be expected? It’s a tiny bit of forged metal. I’d put money that they came from the same factory.

Most disagreemnet you’ll get is people trying to feel better about spending £30 on a 1inch bit of metal.