If you have some machining ability, take a piece of flat stock, cut it about 3" long and mill two 3/8" openings in either end. I used a replacable 3/8" drive stud out of a SO 1/2" to 3/8" adaptor in one end. I use this with crowfeets all the time getting at hard to reach fittings. Also works to turn a crowfoot into a super short wrench.