A slider for slide fasteners may include a slider body and a closure part. The closure part may include a closure portion for closing the gap between a free end portion of a pull tab attachment post and an upper blade; an upper engaging portion provided above the closure portion and engageable with the free end portion of the pull tab attachment post and a leg portion provided below the closure portion. The leg portion may include a rod portion extending from the closure portion along the coupling post and a lower engaging portion coupled to the rod portion and engageable with a lower blade.