Are there alternatives to Shutter-lok fasteners?
Shutter-loks are basically vinyl nails with annular rings to grip. They are meant to be removable by snipping them, confirming that they have low strength.

Why not simply use screws of a similar length? You need a weatherproof type, such as these which are recommended for shutters.



You could also use coated deck screws which come in several colors and weather well.