I always use Opal Sock yarn and this is no exception. Here's a photo of the ball labels. I have no idea if it is still available or not.
This evening I have completed a pair of children's socks in the same yarn - photo to follow when they have been blocked and pressed. I am in awe that my Grandmother managed to decipher the complicated knitting instructions but the DBEM assures me that Grandma knitted her school socks.