Mill spun white Ryeland, from the Weredena small holder flock, in Suffolk. These colours match the Ryeland Rainbow yarns, and the Manx/Ryeland woven fabric. 
The yarns are dyed with many plants but include  Blackthorn, Hazel, Madder, Woad, Xanthoria lichen, Purging Buckthorn, Weld, Holly and Heather.  
Mounted on a sturdy brass keyring finding. 
 
And what the heck is a thrum? A thrum is the last of the threads on a warp that come up behind the heddles and don't make it into a weave. There are lots of uses for thrums, and this is one of my favourites :)