You will simply need a screw that is 1/4" diameter or less for the Chrome Bracket and Single Wire Plug for Thin Line Trailer Clearance and Side Marker Lights # A67CB.
Most people re-use the hardware that is already on their trailer but if that won't work you'd need to source the screws at a local hardware store. view full answer...
The industry standard is 4 inches so we do not have anything that is 4.5 inches square.
However we do have the Bulldog Square Jack - Drop Leg w/ Non-Spring Return - Sidewind - 26" Lift - 12,500 lbs # BD182700. This is a sidewind leg jack that is 4 inches square.
If you need a new cranking handle you can find one here. Replacement Bulldog Sidewind Jack Crank Assembly w/ Vertical Clevis - 13-1/2" Radius - Black # BD015181
If you send me pictures of your equipment I can better advise you... view full answer...