The DEWALT DW2547IR 1/4-Inch Hex Shank To 1/2-Inch Socket Adaptor. Impact Driver Rated Socket Adaptors - Best In Class Durability. Drive Size: 1/4 in (hex), 1/2 in (square). Commonly used by Mechanical Contractors - HVAC, Deck Builders, General Contractors, Overhead Garage Door installers.