tre inner track rods

I'm looking to replace my inner track rods and have seen lots of posts which refer to a plastic fitting which sometimes needs to be split in order to get the crows foot spanner in there. I can't seem to find those plastic parts anywhere: could someone point me in the right direction to a supplier?

Anyone know the size ? I've looked on the rack but there's no sticker on it grrr. Going to get them from Euro car parts in the black Friday sale. Cheers