A specialty crafting table granted by the Guerilla specialty, required to build the best magic-based traps.
The Advanced Trap Maker's Workshop is listed among the benefits of the Guerilla specialty. Carl describes it as a specialty crafting table, one he really wanted to get, and notes that the advanced version is required to build some of the best magical-based traps.
He distinguishes it from the Advanced Bomb Maker's Workshop: despite the similar names, the trap workshop is just a table while the bomb workshop is an entire room. That difference, plus the recipes waiting in his cookbook, is why he ultimately passes on Guerilla.
A specialty crafting table.
The crafting bench Carl gave up when he declined the Guerilla specialty.