Griot's Garage Boss Micro Rotary Extension Drive This 3 1/2 extension further distances the Boss Micro Rotary Extension Drive tool body from the surface, improving access to tight and intricate body panels and components. Features: Improves access to tight and intricate body panels and components Fast-change drive system for tool-less swapping between drive assemblies Compatible with 1 and 2 Boss Micro Backing Plates Precision-machined and balanced for smooth operation