Most of the 90° drill attachments we've tested over the years have failed miserably. Typically the plastic casing breaks under stress, or you have to remove your drill chuck to install the thing. Phewy!
Ours has a heavy duty all-metal housing and it attaches directly to any 3/8" or larger drill chuck. It comes with a 3/8" keyless chuck, so there's nothing to lose and nothing to assemble. It's mighty handy for drilling in tight spots, or for using sanding accessories. 6-1/2" overall length. Right angle leg is 4-1/8" long without drill bit or driver.
Not for use in hammer drills or in tools with hammer or chisel mode.