Thank you for asking. The exact Allen wrench size depends on the specific outdoor bench model and the bolts included in its hardware pack. There is no single size that fits every bench we manufacture. That said, most of our outdoor benches are assembled with metric hex-socket bolts, and the most common Allen wrench sizes are 5mm and 6mm.

A 5mm Allen wrench is typically used for M6 bolts, while a 6mm wrench is common for M8 bolts. Some smaller fittings, such as armrest brackets or decorative caps, may use a 4mm wrench. Heavier leg or frame connections may occasionally require an 8mm wrench. If your bench uses imperial hardware instead of metric, you may need a 3/16-inch, 7/32-inch, or 1/4-inch hex key.

To confirm the correct size, check the assembly manual or the label on the hardware bag. Many outdoor benches include the required Allen wrench in the box. If the manual is missing, look at the hexagonal socket in the bolt head. You can also test-fit a metric Allen wrench set: start with 5mm, then try 6mm. Do not force a wrench that feels too loose or too tight, because it can strip the bolt head or round out the socket.

If you purchased your bench directly from our outdoor bench factory, send us your model number, order number, or a clear photo of the bolt head. Our support team can then confirm the exact Allen wrench size for your specific bench. For most customers, keeping a 5mm and 6mm Allen wrench nearby is the safest choice during assembly.