I think they are for seamstress and tailors, my wife and mother have a few like those in there sewing kits and i have seen them at fabric and craft stores.
I have a 3/8 drive square impact and i just use a 3/8 square to 1/4 hex adapter.
This:
http://www.homedepot.com/p/t/202196524?storeId=10051&langId=-1&catalogId=10053&productId=202196524&R=202196524#.UYgOeZWiDIo
With this...
The part number should be CHTSS38117M (17 piece set) , it seams to be missing 2 (8-9mm) sockets and one 6" extension. and about $10 more the the SAE set
I just got the 3/8" M12 ratchet and I went that route cause I use 3/8th drive a lot and if I need to use 1/4 drive socket I will just use an adapter. I may down the road but the 1/4 drive M12.
This is what i have and like it a lot, http://www.summitracing.com/parts/ttn-11072/overview/ it the same as the match or Mac can't remember which, but with a different grip.