It's a pass thru socket wrench drive extension for socket wrenches. Kind of found it looking for alternatives to the new m12 pass thru wrench. The one on the bottom would be nice to have except my pass thru socket are 19mm drive and not spline drive.
spectools.com

Upgraded Powerbox Conversion Attachment Set for 3/8" and 1/4" drive power ratchets-Model PBS-1438
POWERBOX DRIVE HEAD WORLDWIDE PATENTS PENDING New Upgraded model replaces PBS 1420. Converts either 1/4" or 3/8" drive mini head air or cordless ratchet to low profile box wrench output. 1/4" to 3/8" drive adaptor included Head fits most 1/4" and 3/8" power ratchets with round necks up to...
