Standard 1/4" bolts have a 3/8" head and and use a 3/8" square socket. 

Some special 1/4" lag bolts with over-sized head - 7/16" head.

This product has minimum quantities.

500 piece discount = 20% off

1000 piece discount = 30% off

Square Head Lag Bolt Measurement Annotation: Lags Bolts - The diameter x length under the head

Head size is not included in standard annotations for lag bolts.