Includes one complete set of hardware (screws, nuts, etc.) for the selected product (unless specified otherwise). For instance, the spare hardware set for the MLOK to ARCA Rail Adapter (Short and Long Variants) comes with two MLOK Nuts, two flathead MLOK Nut screws, and 4 small (but optional) stop screws.
To be transparent, it often costs us $4-6 to ship you hardware because USPS will reject and return a shipment if screws are put in a regular envelope. The amount charged here just covers the shipping, the hardware is free.