I Found These In a Group of Snap On I Just Purchased...I Thought They Were Regular Swivel Sockets till I Saw the Sizes...Found them in a Snap On Catalog and it Looks to Be a Full Set of British Standard Flexockets

Part Numbers are:

3/8 BSF WFU-101, 5/16 BSF WFU-100, 1/4 BSF WFU-99, 2BA WFU96

So Far I Have Found 17 Whitworth Snap On Wrenches, 4 Blue Point Whitworth Wrenches, 11 - 1/2" Drive Whitworth Snap On Sockets, 8 Other Brand Assorted Whitworth Wrenches and 4 Hazet 450 (Porsche 356 "Little a") Wrenches....And I Wasnt Expecting Any of them When I Bought This Lot!

I Bought the Snap On's Blind Not Knowing their Size or What Ones Were Included...all the Rest Came in a Kennedy Toolbox at the Bottom Covered in Tools!

Geesh! Talk about a needle in a haystack. Nice stuff!

I have the middle two of the set.