Up until June of 2018, our truss rods have required a 5mm wrench (Allen wrench, Allen key, hex wrench, or hex key). Any guitar purchased in June 2018 or sooner now require a 4mm allen wrench. Some older guitars used 5/32″ wrench. Any hardware store should also carry a wrench of the correct size.
Our truss rod is a “double action” truss rod developed to work on both a forward & backward bow.
Truss rod adjustment involves many subtleties. If you have no prior experience adjusting truss rods, or if a simple adjustment does not give you the desired outcome, we recommend taking your guitar to an experienced technician.