3/8" x 2.1/4" UNC Hex Bolt. These bolts have a hex head and also have a shoulder.
Angled Stretcher Brackets Plates 38 x 26.5 x 26.5mm 290.08.961 x 10pcs of Hafele
10 x Stretcher Plates Galvanised Finish 38 x 28 x 25mm (Hafele) 290.08.961
100pcs x Angled Stretcher Brackets Plates 38 x 26.5 x 26.5 mm 290.08.961 Hafele
Brackets Plates Hafele Angled Stretcher 38 x 26.5 x 26.5mm - 290.08.005 x 10
100pcs x Angled Stretcher Brackets Plates 38 x 26.5 x 26.5 mm 290.08.005 Hafele
Gorffy Angle Brackets 15PCS, L Bracket 30 x 30 x 38 x 1.2 mm, Stainless Steel Sleeper Brackets with 90 Screws, Heavy Duty Right Angle Corner Bracket for Wood, Metal Corner Braces for Fixing Timber